grumpyvette

HERES AN OLDER POST THAT MIGHT HELP, [/b] A Word On Fuel Pressure Fuel pressure regulators should be set to a flowing fuel pressure or false readings may be obtained. To set flowing fuel pressure on the vehicle, use a test jet flowing fuel into a container to find what size test jet should be used when flowing multi-nozzle systems. Use the following formula: Jet size2 x number of nozzles (per fuel solenoid). Then take the square root of this number. This is the Test Jet in thousands of an inch. Example: Eight #32 Fuel Jets are equal to one 91 Jet 32 x 32 = 1024 x 8 Jets = 8192 The square root of this number is 90.509... This procedure cannot guarantee a steady fuel pressure during a run. As G-forces and cell placement will affect the fuel pump's load. Which cannot be easily duplicated in the pits. NOTE: Systems using multiple stages and/or H.P. levels over 400 H.P. will benefit from a super Hi-Flo bottle valve (PT.# 16139) and/or a large bottle (15 or 20lb.) Due to a lower pressure drop during a run. This valve also allows pressure readings with a closed bottle valve; via one of the valve's built-in direct reading ports, one 1/8 NPT and one 1/4 NPT. * A 15 pound bottle equipped with a super Hi-Flo valve works great on maximum effort systems (with a minimum effect on weight). Q: Can I simply bolt a nitrous kit onto my stock engine? A: Yes. NOS manufactures systems for virtually any stock engine application. The key is to choose the correct kit for a given application; i.e., 4 cyl. engines normally allow an extra 40-60 HP, 6 cyl. engines usually work great between 75-100 extra HP, small block V8's (302/350/400cid) can typically accept up to 140 extra HP, and big block V8's (427-454) might accept from 125-200 extra HP. These suggested ranges provide maximum reliability from most stock engines using cast pistons and cast crank with few or no engine modifications. Q: What are some of the general rules for even higher HP gains? A: Generally, forged aluminum pistons are one of best modifications you can make. Retard ignition timing by 4-8 degrees (1 to 1-1/2 degrees timing retard per 50 HP gain). In many cases a higher flowing fuel pump may be necessary. Higher octane (100+) racing type fuel may be required as well as spark plugs 1 to 2 heat ranges colder than normal with gaps closed to .025"-.030". For gains over 250 HP, other important modifications could be necessary in addition to those mentioned above. These special modifications may include a forged crankshaft, a high quality race type connecting rods, a high output fuel pump dedicated to feeding the additional fuel demands of the nitrous system, and a racing fuel with high specific gravity and an octane rating of 110 or more. For more specific information about your application, please contact the NOS technical dept. Q: How does nitrous work? A: Nitrous oxide is made up of 2 parts nitrogen and one part oxygen (36% oxygen by weight). During the combustion process in an engine, at about 572 degrees F, nitrous breaks down and releases oxygen. This extra oxygen creates additional power by allowing more fuel to be burned. Nitrogen acts to buffer, or dampen the increased cylinder pressures helping to control the combustion process. Nitrous also has a tremendous "intercooling" effect by reducing intake charge temperatures by 60 to 75 degrees F. Q: What kind of testing or research is performed on NOS products? A: NOS maintains a complete research and development center including computerized dynamometer equipment as well as a nitrous/fuel flow testing facility. In addition, NOS is actively involved in many aspects of racing; working closely with many top name racers to develop the most powerful and reliable nitrous systems in the world. Q: How much performance improvement can I expect with a nitrous system? A: For many applications an improvement from 1 to 3 full seconds and 10 to 15 MPH in the quarter mile can be expected. Factors such as engine size, tires, jetting, gearing, etc. will affect the final results. Q: How long will the bottle last? A: This largely depends on the type of nitrous kit and jetting used. For example, a 125 HP Power Shot kit with a standard 10 lb. capacity bottle will usually offer up to 7 to 10 full quarter-mile passes. For power levels of 250 HP, 3 to 5 full quarter-mile passes may be expected. If nitrous is only used in 2nd and 3rd gears, the number of runs will be more. Q: How long can I hold the nitrous button down? A: It is possible to hold the button down until the bottle is empty. However 15 continuous seconds at a time, or less, is recommended. Q: When is the best time to use nitrous? A: At wide open throttle only (unless a progressive controller is used). Due to the tremendous amount of increased torque, you will generally find best results, traction permitting, at early activation. Nitrous can be safely applied above 2,500 RPM under full throttle conditions. Q: Does NOS manufacture 50-state legal nitrous systems? A: Yes. In fact, NOS has several EO numbers for various kits such as the 5.0L Mustang and 305/350 GM V8's, etc. In addition, there is no need to remove any smog equipment when installing an NOS system. For more information call the NOS tech line. Q: Will I have to re-jet my carburetor on my car when adding nitrous? A: No! The NOS system is independent of your carburetor and injects its own mixture of fuel and nitrous. Q: Is nitrous oxide flammable? A: No. Nitrous Oxide by itself is non-flammable. However, the oxygen present in nitrous oxide causes combustion of fuel to take place more rapidly. Q: Will nitrous oxide cause detonation? A: Not directly. Detonation is the result of too little fuel present during combustion (lean) or too low of an octane of fuel. Too much ignition advance also causes detonation. In general, most of our kits engineered for stock type engines will work well with premium type fuels and minimal decreases of ignition timing. In racing application where higher compression ratios are used, resulting in higher cylinder pressures, a higher fuel octane must be used as well as more ignition retard. Q: Where can I get my bottle refilled? A: Simply call 1-800-99-REFILL for the location of the nearest NOS dealer with refilling capabilities, or check immediately for the most up-to-date Authorized NOS Refill Station Dealers List online. Q: Is there any performance increase in using medical grade nitrous oxide? A: None! NOS recommends and sells only the automotive grade, called Ny-trous Plus. Ny-trous Plus contains a minimal amount of sulfur dioxide (100 ppm) as a deterrent to substance abuse. The additive does not affect performance. Q: Is it a good idea to use an aftermarket computer chip in conjunction with an NOS System? A: Only if the chip has been designed specifically for use with nitrous oxide. Most aftermarket chips use more aggressive timing advance curves to create more power. This can lead to possible detonation. You may wish to check with the manufacturer of the chip before using it. The top manufacturers, such as Hypertech do make special chips for use with nitrous. Q: How long does it generally take to install an NOS kit? A: The majority of NOS kits can be installed using common hand tools in approximately 4 to 6 hours. NOS instruction manuals are by far the best in the industry; and include specific installation drawings, wiring diagrams, and bottle mounting procedures as well as performance tips and a thorough trouble shooting guide. Q: Which type of manifold is better suited for a plate injector type of nitrous system, single or dual plane manifold? A: As long as the manifold doesn't interfere with the spray pattern of the bars, either will work fine in most cases. The distribution is better with a single plane at high RPM. If your goal is to increase power by more than 150 HP, the single plane manifold is better. Q: Does nitrous oxide raise cylinder pressure and temperatures? A: Yes. Due to the ability to burn more fuel, this is exactly why nitrous makes so much power. Q: Are there any benefits to chilling the nitrous bottle? A: No. Chilling the bottle lowers the pressure dramatically and will also lower the flow rate of the nitrous causing a fuel rich condition and reducing power. On cold evenings you might run on the rich side. For optimal running conditions, keep bottle pressure at approximately 900-950 psi. NOS has a nitrous pressure gauge that allows you to monitor this. If you live or operate a nitrous system in colder temperatures, it may also be a good idea to purchase a bottle heater kit, part #14164. Generally, ambient temperatures of 80-90 degrees F will allow for best power potential of NOS kits. Q: Are there benefits to using nitrous with turbo or super-charger applications? A: Absolutely! In turbo applications, turbo lag is completely eliminated with the addition of a nitrous system. In addition, both turbo and superchargers compress the incoming air, thus heating it. With the injection of nitrous, a tremendous intercooling effect reduces intake charge temperatures by 75 degrees or more. Boost is usually increased as well, adding to even more power. Q: How complete is an NOS kit? A: NOS prides itself on offering the most complete systems on the market today. They include virtually every component that may be needed for a complete installation; parts such as extra long carburetor studs, gaskets, pipe tap, fuel hose, brackets, filters, fittings, hardware, wiring, 10 lb. bottle with Hi-Flo valve, comprehensive instruction manual, and all other major components are standard in every NOS kit. Q: What is the difference between a standard and an NOS Hi-Flo bottle valve? A: The orifice of the Hi-Flo valve is much larger than the standard valve allowing for a larger flow of nitrous. With a small orifice valve a pressure drop could occur when nitrous flow is high; causing surging or inadequate nitrous flow. The NOS Hi-Flo valve eliminates this problem. NOS Hi-Flo valves are standard in all NOS kits. Q: What affect does nitrous have on an engine with considerable miles on it? A: This depends largely on the actual condition of the engine components. Any performance modification to an engine that is worn out or poorly tuned will have detrimental effects. However, an engine in good condition, with good ring and head gasket sealing, should be able to use nitrous without any abnormal wear. Q: Will the use of nitrous oxide affect the catalytic converter? A: No. The increase in oxygen present in the exhaust may actually increase the efficiency of the converter. Since the use of nitrous is normally limited to 10-20 seconds of continuous use, there usually are no appreciable effects. Temperatures are typically well within acceptable standards. Q: Will the percentage of performance increase be the same in a highly modified engine compared to a stock engine when using the same NOS kit and jetting? A: Not really. In most cases the percentage of increase is greater from a stock engine because it is not as efficient as the modified engine in a normal non-nitrous mode. However, since the effects of nitrous oxide magnify the output of any engine, the total power output will be much higher in the modified engine. Q: Can high compression engines utilize nitrous oxide? A: Absolutely. High or low compression ratios can work quite suitably with nitrous oxide provided the proper balance of nitrous and fuel enrichment is maintained. NOS kits are used in applications from relatively low compression stock type motors to Pro-Modifieds, which often exceed 15 to 1. Generally, the higher the compression ratio, the more ignition retard, as well as higher octane fuel, is required. For more specific information talk to one of our technicians. Q: Can service station fuel be used for street/strip nitrous oxide applications? A: Yes. Use of a premium type leaded or unleaded fuel of 92, or greater, octane is recommended for most applications. Many NOS systems are designed for use with service station pump gas. However, when higher compression or higher horsepower levels are used, a racing fuel of 100 octane, or more, must be used. Q: What type of cam is best suited for use with nitrous oxide? A: Generally, cams that have less exhaust overlap and more exhaust duration. However, it is best to choose a cam tailored to normal use (when nitrous is not activated) since 99% of most vehicle operations is not at full throttle. There are special cam grinds available for nitrous competition which have more aggressive exhaust profile ramping, etc. Since cam selection depends largely on vehicle weight, gearing, etc., it is best to stick to cam manufacturers' recommendations for your particular goal. Q: Are NOS kits applicable on late model EFI cars? A: Yes. In fact NOS has by far the most comprehensive selection of nitrous kits available for these cars. Call for your specific application if you do not see it listed. Q: What type of nitrous system is better; a plate injection system or a direct port injection system? A: The advantages of a plate system are ease of installation and removal, ability to transfer easily to another vehicle, ability to change jetting combinations quickly, and in most cases, provide you with all the extra HP you will ever need (75 to 350 more HP). In some cases, such as in-line type engines with long runners, a direct port type system is advisable for maximizing distribution. Also, where more than 350 HP is needed, our direct port Fogger systems will provide the ultimate in distribution and power (up to 500+ HP). Direct port injection is also desirable when the system is hidden under the manifold. Q: Should I modify my fuel system to use nitrous oxide? A: Most stock fuel pumps will work adequately for smaller nitrous applications. It is important to check to see if your pump can flow enough fuel to your existing fuel system (whether carburetor or fuel injected), as well as being able to supply the additional fuel required by the nitrous kit under full throttle conditions. It may be a good idea to dedicate a separate fuel pump to the nitrous kit. Q: Which is the best position to mount a nitrous bottle? A: NOS bottles come with siphon tubes and, in order to maintain proper nitrous pickup, it is important to mount the bottle correctly. We recommend mounting the bottle at a 15 degree angle with the valve end higher than the bottom of the bottle. The valve end of the bottle should point to the front of the vehicle and the valve knob and label should face straight up. Q: How important is it to use nitrous and fuel filters in a kit? A: Some of the most important components of any nitrous system are nitrous and fuel filters. To keep contaminants from attacking the solenoid or plugging up a jet, NOS nitrous filters feature a special stainless steel mesh element from the aerospace industry. Q: What are the advantages of using nitrous compared to other performance options? A: The cost of many other performance options can put you in the poorhouse. Dollar for dollar, you can't buy more performance with less money than nitrous. With a nitrous system, performance and reliability can be had for a much more reasonable price while still retaining the advantage of a stock engine during normal driving. And, Nitrous offers tremendous gains in torque without having to rev the engine to excessive rpm's. These factors help your engine last longer than many other methods of boosting horsepower. Q: Does NOS manufacture kits for motorcycles, water craft, or snowmobiles? A: Absolutely. Call or write NOS to obtain our special catalog devoted specifically to these applications. Q: What kind of pressures are components subject to in a typical nitrous kit? A: Pressures often exceed 1,000 psi. This is why NOS uses only high pressure tested aircraft quality components like stainless steel braided Teflon lines throughout its system. Q: How do I know how much nitrous is left in the bottle? A: The most reliable method was is to weigh the bottle to determine how many pounds remain. When a bottle is near empty (about 20% or less nitrous remaining) a surging effect is normally felt. Q: What is the function of the blow-off safety valve on the bottle? A: It is very important not to overfill a bottle; i.e., a 10 lb. capacity bottle should not be filled with more than 10 lbs. of nitrous oxide by weight. Over-filling and/or too much heat can cause excessive bottle pressures forcing the safety seal to blow and releasing all the contents out of the bottle. Q: Will I have to change my ignition system? A: Most late model ignition systems are well suited for nitrous applications. In some higher HP cases, it may be advisable to look into a high quality high output ignition system. CONTINUE READING for carbs very good system http://www.centuryperformance.com/images/tech/fuel3.gif not quite as good, but still ok http://www.centuryperformance.com/images/tech/fuel4.gif

this may help

just some info, just one of those magnets can lift a sbc cylinder head, and yes they work exceptionally well at trapping metalic dust I normally place (4) one in each corner of the oil pans sump to prevent metalic dust from reaching the oil pump pick-up once you get them and install them youll see how much crud they prevent from reaching your bearings the next time you pull the oil pan, and never forget to use them in future engine rebuilds. BTW the site mentions that they can loose strength if heated over 250 degrees, don,t worry about it, the magnets stay well under 250 degrees even if the oil gets close to 250 degrees, because they are in firm contact with the oil pans lower inside surface and that lower outside surface outer surface is in direct contact with the outside cooler air, in the many years Ive used them they have NEVER showed any tendency to lose strength, if your worried about it just J&B weld them to the outside surface of the oil pan sump, they will work almost as well that way http://www.wondermagnets.com/cgi-bin/edatcat/WMSstore.pl?user_action=detail&catalogno=0001

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1770&prmenbr=361 for those of you not familiar with these they slip between the block and spin-on oil filters, they don,t work on all sizes of oil filters, and they are not designed to replace frequent oil filter changes or allow longer times between oil changes keep in mind the MAIN PURPOSE of pre-screens is to allow you a easy look at a SAMPLE OF the metalic, gasket,silicone and plasic crud that the oil system is pushing thru your engine,they are not designed to be filters,they do not trap 100% of the crud,(neither does your oil filter for that matter, they, the pre-screens, are designed to allow you to spot bearing or cam lobe wear quickly, but they only work if you take the time to INSPECT them frequently by spinning off the fillter and inspecting them, the average oil filter has between 200 and 450 sq inches of filter area, thes pre-screen have less than 10 sq inches of filtering area,so they are easily at least partly blocked with crud and can and do restrict oil flow if you NEGLECT to inspect and clean them FREQUENTLY we used them all the time on race engines that we worked on every week , and in that application they are a great help in catching problems before they become major, but if your like most guys and only take the oil filter off durring 3000 mile oil changes THEY ARE A BAD IDEA for THAT APPLICATION BTW most guys running race engines DON,T USE THEM as the ONLY source of info on engine condition MOST guys also cut open and inspect the oil filters themselfs to look for bearing material and signs of engine wear now Ive said this before, you also should have installed the good magnets in your engines oil pan, simply because they can trap and hold most of the metallic dust that a failing cam and lifter generates from getting constantly pushed back into your engine to cause furthe damage http://www.wondermagnets.com/cgi-bin/edatcat/WMSstore.pl?user_action=detail&catalogno=0001

first thing you need to do is FIND OUT WHAT CAUSED THE OLD CAM TO FAIL,THEY DON,T JUST HAVE FAILURES,THERES A CAUSE!! first read this http://www.cranecams.com/instructions/valvetrain/camfail.htm let me say this, in 38 years of building engines and working on cars Ive seen my share of guys with flat cam lobes and 99.999% of the time the CAUSE is either failure to break-in the cam correctly (ABOUT 10%) or FAILURE TO CAREFULLY CHECK ALL THE CLEARANCES,and/or the VALVE TRAIN GEOMETRY and VALVE SPRING PRESSUREs (ABOUT 89%) now you can ignore what I say,.... but chances are excellent, youll be replaceing a second cam if you do! BTW just some info, all that metal from the lifters and cam lobes did not vanish! its now floating around in your engine somewhere and not all of it got caught in the oil filter, at the bare minimum, change the oil and filter, but you should pull the pan and clean the engine at least! and the correct thing to do is to pull the engine for a cleaning of the oil passages in the block and a careful check of the rings and bearings

nice job! having built several sets of custom headers in the past I know both the P.I.T.A. involved and the sence of true accomplishment getting it done correctly produces

you might want to look over this site and call for ideas/questions, http://www.ratsun.com/ having worked on one of those cars and help complete the swap in the past I can tell you that, youll need a full roll cage and sub frame, youll need a total rework of the rear suspension and brakes,the best weay we found was to basically build a rolling chassis and complete roll cage after carefully taking measurements and cutting almost all the datsun body away and making your own firewall,flooring and rear suspension, but the swaps been done several times and it makes for a truely nice car, especially if you take your time, and do it correcly, the BIG BLOCK EQUIPED with aluminum heads,intake and water pump weights less than 70 lbs more than a all iron small block

I found this info and I figured you guys might like to look it over, now the first thing I want to point out is where the DATA came from. and KEEP IN MIND ITS REAR WHEEL HP AND The TPI INTAKE IN THE TEST consists of 58mm TB, fully ported plenum, AS&M large tube runners, and highly ported Edelbrock base WHICH MEANS ITS ALREADY MAKING AT LEAST 25HP-30HP MORE THAN A STOCK TPI INTAKE) http://www.eecis.udel.edu/~davis/z28/winter01/dyno/ The engine was basically the same,in all the test except for the intake manifold, consisting of a ZZ4 crate motor, AFR190 heads, LT4 HOT cam, and SLP 1-3/4" SS headers. Trans is a 700r4 with a Vigilante 2800 stall converter. The Engine Control Module (ECM) was a '92 TPI stock ECM (MAP/speed-density) with a modified EPROM. I HAVE GONE TRU AND WILL PICKED OUT THE IMPORTANT POINTS TO SAVE YOU TIME IN THE CHARTs AND GRAPHS ON THE SITE TPI engine.....283 PEAK rwhp @4800rpm peak AVG. TQ 291.5 AVG HP 269.5 thats 38 more peak hp than stock miniram 303 PEAK rwhp @6200rpm peak AVG. TQ 285.8 AVG HP 269.1 IT LOST 29 HP at 3800 rpm and MADE 48 MORE HP THAN THE stock TPI at 6300 RPM stealth ram 342 PEAK rwhp @6400rpm AVG. TQ 319 AVG HP 300 it lost 28 hp at 3600 rpm BUT GAINED 66 HP AT 6600 RPM over the stock TPI 342 rear wheel hp is aproximatly equal to 427 flywheel HP FROM A 350 SBC ENGINE, figuring a 20% driveline loss rate. the use of a longer duration cam and only measureing PEAK HP would tend to benefit the miniram and STEALTH RAM intakes to a MUCH GREATER extent than the TPI, THATS HOW claims of gains of 100hp are made for some intake combos, while its TRUE that you can make in excess of a HUNDRED EXTRA hp at 6600rpms is due more to the TPI not being able to flow air (LOSSES) keep in mind that a LARGER ENGINE DISPLACEMENT WOULD BENEFIT EVEN MORE from the steathram link to c-4 stealthram increasing the displacement from 350 to 383 and the compression ratio to 11:1 , adding the stealth ram and a cam like the CROWER #00471 or CRANE #119661 will get you over 450hp/450tq with a good set of heads like those 190cc AFR mentioned

PORT SIZE FLOW AND THE RELATION TO CAM DURATION FIRST, This will not be anything more that a brief glimpse into a subject that takes years to understand fully and I’m sure there are a few people on the site that can give more exact info! This is meant to apply to the 350-383 sbc engines most of us are useing My purpose is merely to give an idea as to the relationship between the factors and yes IM ignoring several minor factors to make things easier to understand like dynamic compression and valve timing overlap But lets look a a few concepts (1) There are 720 degrees in a 4 cycle engines repetitive cycle of which between about 200degrees to about 250 degrees actually allow air to pass into the cylinder, (the valves open far enough to flow meaningful air flow) and the piston has a maximum ability to draw air into that cylinder based mostly on the engines displacement and the inertia of column of air in both the intake port and the suction (or negative pressure the PROPERLY designed headers provide) this produced a max air flow thru the ports, the greater the volume of fuel/air mix effectively burn per power stroke the greater the engines potential torque production, the faster you spin an engine the greater the NUMBER OF POWER STROKES PER MINUTE, and up to the point where the cylinder filling effectiveness starts falling off due to not enough time available to fill that cylinder the torque increases, above that rpm or peak torque it’s a race between more power stokes and lower power per stroke (2) look at this diagram (3) As air enters an engine it normally travels thru both an intake system and the cylinder heads intake port to eventually pass into the cylinder thru the valve. The valves in a normal small block corvette engine are between 1.94 and 2.08 in diameter, that’s between 2.9sq inches and 3.4 sq inches of area, but because the valves require a seat that at a minimum are about 85%-90% of that flow area we find that the intake port even with out any valve has a max flow of not more than about 90% of the flow thru a port of valve size. Or in this case 2.46 sq inches-2.9 sq inches of port area, Since you gain little if any flow having a port that’s substantially larger than the valves AT NORMAL ATMOSPHERIC pressures and since you can’t substantially increase the valve sizes for several mechanical reasons you must improve efficiency, this is done in two major ways, you can match the intake port length and cross sectional area to the engines most efficient rpm range on the intake side, to build a positive pressure behind the intake valve as it opens and match the exhaust length and diameter on the exhaust side to provide a negative pressure to help draw in more volume this will require the cam timing match that same rpm range of course. By experimentation its been found that air flow port speeds in the 200-320 cubic feet per minute range are about the best for a chevy V-8 now lets say you have a 383. 383/8=47.875 cubic inches per cylinder, the rpm range most used is 1500rpm-6000rpm so that’s where are cam and port size must match, you can do the math , (47.875 x ½ engine rpms = cubic inches, divided by your cams effective flow duration, (use 210-235) as a default for a stock cam) x 720 degrees/1728 (the number of cubic inches in a cubic foot) to get the theoretical max port flow required (I will save you the trouble its 250cfm-275cfm at max rpms and about 2.4-2.9 sq inches of port cross section, depending on where you want the torque peak, or use this handy calculator, Intake Runner Area = Cylinder Volume X Peak Torque RPM 88200 Or this helpful site http://www.newcovenant.com/speedcrafter/calculators/intake.htm Either way you’ll find that you’ll want a port size in the 2.4sq –2.9 sq inch area Now use this calculator to figure ideal port length, REMEMBER youll need to add the 6†in the cylinder head to the intake runner length to get the total length and you can,t exceed the engines REDLINE RPM which with hydrolic lifters seldom is higher than 6400rpm http://www.bgsoflex.com/intakeln.html Ever wonder why your engines torque curve gets higher with the engines rpm level until about 4000rpm-5500rpm(DEPENDING ON YOUR COMBO) but fades above that rpm level? well it depends on several factors, first as long as the cylinders can fill completely you get a good fuel/air burn so you get a good cylinder pressure curve against the piston each time the cylinder fires, THE ENGINES TORQUE CURVE INCREASES WITH THE NUMBER OF EFFECTIVE POWER STROKES PER SECOND, at very low speeds there’s not enough air velocity to mix the fuel correctly or produce a effective ram tuning effect but as the rpms increase the cylinders fill very efficiently until the rpms reach a point where the cylinders just don’t have the time necessary to flow enough air through the valves to fill the cylinders , remember a 5000rpm the intake valve out of 720 degs. in each cycle opens for about 250degs of effective flow even with a hot roller cam, now that’s only about 35% of the time and there’s 41.6 intake strokes per second , that’s only 1/60th of a second for air to flow into the cylinder Its your engines ability to fill the cylinders that increases your power and the more efficiently you do that the higher the rpm level you can accomplish that at the more power your engine makes, remember the formula for hp is (torque x rpm/ 5252=hp) so moving the torque curve higher in the rpm range increases hp but at some point the time available to fill the cylinders becomes so short that efficiency begins to drop off rapidly, the peak of efficiency is reached normally in the 4500rpm-5500rpm range, and as rpms increase its a race between more power strokes per minute trying to raise the power and the increasingly less effective percentage of cylinder filling dropping the power. Volumetric Efficiency The volumetric efficiency of a 4-stroke engine is the relationship between the quantity of intake air and the piston displacement. In other words, volumetric efficiency is the ratio between the charge that actually enters the cylinder and the amount that could enter under ideal conditions. Piston displacement is used since it is difficult to measure the amount of charge that would enter the cylinder under ideal conditions. An engine would have 100% volumetric efficiency if, at atmospheric pressure and normal temperature, an amount of air exactly equal to piston displacement could be drawn into the cylinder. This is not possible, except by supercharging, because the passages through which the air must flow offer a resistance, the force pushing the air into the cylinder is only atmospheric, and the air absorbs heat during the process. so, volumetric efficiency is determined by measuring (with an orifice or venturi type meter) the amount of air taken in by the engine, converting the amount to volume, and comparing this volume to the piston displacement. this increases until the torque peak then falls as the rpms increase. Here is a rough guide to match duration to port flow at different rpm level if you’ve been following along you’ll find that you’ll need intake ports about 2.3-2.9†sq inches in cross section, and between 12†and 21 “ long (DEPENDS ON WHERE THE ENGINE IS DESIGNED TO MAKE MAX HP) and cam timing in the 215@.050 to -240@.050 lift range, as the rpms or displacement increase either the port flow or the cams duration must increase or the engines cylinder fill efficiency rpm will drop! Now this is important, as the port flow efficiency goes up though the use of longer and larger intake ports the cam duration could remain the same or even be lower and you get more efficient cylinder filling as the rpms increase, that’s why high efficiency port designs like on the LS1 can use lower duration cams to flow similar total air flow thru the ports than the lower efficiency ports like the old fuelie heads could but at some point all ports reach max flow and an increase in the time the valves remain open at higher rpms increases the cylinder fill efficiency and that increases the engines ability to make torque at that rpm range if you pick a smaller runner or longer runner you should pick a cam with a shorter duration to match the resulting lower torque peak that will likely result

that plan is so vague that it reminds me of the guy who said on graduating high school(Ive got my whole life planed out "IM GOING TO BECOME FILTHY RICH AND MARRY A PRETTY GIRL AND LIVE TO BE 120 YEARS OLD" well like in the above plan.... its the little details about how youll do it, the costs and effort involved,how long it will take,who can or will help you, and what youll use to do it , the problems you run into, and how you solve them,that potentially screw things up! if your NOT particularly interested in tearing the car apart and learning how to put it back togeather with dozens of modifications including learning how to CORRECTLY BUILD ENGINES,WELD,BUILD/MODIFY,SUSPENSIONS,FRAME MODS,and your NOT into having the car sit for 5 month too several years while you do it ,my advise would be to buy a car thats already converted or buy a corvette,with a high hp engine already in it, youll surely have less money invested and less time wasted,in the long run. BUT IF YOU WANT TO GAIN SKILLS,KNOWLEDGE,AND PRIDE OF DOING THE WORK YOURSELF,THEN JUMP ON IN,READ ALL THE BACK POSTS AND GET READY TO HEAR YOUR WALLET WIMPPER IN AGONY YES YOU CAN BUILD A KILLER (Z) but its not going to happen in one month and its not likely to happen on a reasonable budget, and its not likely to cost anywhere near what you expect going into the project! most of the guys may not admit it but by the time you get the car correctly rebuilt, with a good high hp engine youll more than likely have $10,000PLUS and at least a year into the project!! you need to sit down and make a list of all the mods and the goals you have for that car, then make a list of whats involved in each mod and set a budget and time frame for each mod, ask questions, buy tools , make friends, and follow throught on those goals/mods in a logical well thought out plan! Ive done it 8 or 9 times now,(Z SWAPS) and Ive built/restored and modified over 37 corvettes in the last 34 years,(IVE LOST COUNT SIMPLY BECAUSE ITS ALMOST A WEEKLY THING FOR THE LAST 34 YEARS) ITS A HOBBY FOR GUYS WHO ENJOY SOLVING PROBLEMS,WELDING,SEARCHING FOR PARTS,BUILDING AND FITTING CUSTOM MADE ASSEMBLYS and doing BODY WORK; JUST SO YOU KNOW WHAT YOUR GETTING INTO! AND YES THE END RESULTS ARE NORMALLY WORTH THE EFFORT AND COSTS INVOLVED

just some info look over these engine combos and find which is the closer match to your combo! theres lots of factors that effect the results but in general if your cam is under 235 dur.@.050 lift and uses hydrolic lifters if your engine spends most of its time under 4500rpm if your not running a free flow exhaust and headers if your compression is under 10:1 if your cylinder heads flow less than 240cfm @.500 lift if you running a 2.57 to 3.55 rear gear if your car weights over 3400lbs youll be more than likely in the combo where a dual plane intake works better your cam is over 235 dur.@.050 lift and use solid lifters if your engine spends most of its time over 3500rpm if your running a free flow exhaust and headers if your compression is over 10:1 if your cylinder heads flow more than 240cfm @.500 lift if your running a 373-5.13 rear gear if your car weights under 3200 lbs youll be more than likely in the combo where a single plane intake works better you should read this http://victorylibrary.com/mopar/intake-tech-c.htm BTW low raise runners that hit the heads at an angle don,t tend to work well runners that enter at a high angle in line with the ports tend to work better

I posted the links necessary above the soiftware is at the lower part of the site http://www.newcovenant.com/speedcrafter/calculators/compressionratio.htm http://cochise.uia.net/pkelley2/DynamicCR.html lets take my 383 static CPR is 11:1 on paper but 11.07:1 in the real world MY cam is http://dab7.cranecams.com/SpecCard/DisplayCatalogCard.asp?PN=119661&B1=Display+Card my dynamic is 7.9:1

it might help a great deal if you understand that runner length and cross section area have a great deal to do with where the cylinder fill efficiency works best in the engines rpm range, on a 350-383 engine that runner length measured from plenum to the back of the intake valve distance should be about 10"-12" and the cross sectional area should be about 2.3-2.7 sq inches, but remember the DYNAMIC compression ratio,cam timing,(LSA/OVERLAP)displacement, stroke,rod length and exhaust header design also must match that same peak effective level for the best potential power! making the runners longer or the runners smaller in cross section LOWERS THE TQ PEAK, making them slightly shorter or larger in cross setion tends to RAISE the torque peak RPM the exhaust primairys should be at least 18" long and not more than about 32" long before entering the collector and 1.625-1.875 in dia. the collector should be about 15"-22" long and about 2.75 in dia. you might want to play with these calculators http://www.newcovenant.com/speedcrafter/calculators/runnerarea.htm http://www.newcovenant.com/speedcrafter/calculators/intake.htm http://www.newcovenant.com/speedcrafter/calculators/intakecfm.htm http://www.rbracing-rsr.com/runnertorquecalc.html http://www.newcovenant.com/speedcrafter/calculators/compressionratio.htm http://www.nightrider.com/biketech/calc_exhaustlength.htm http://www.btinternet.com/~mezporting/exhaust_length.html http://cochise.uia.net/pkelley2/Overlap.html http://cochise.uia.net/pkelley2/DynamicCR.html http://www.engr.colostate.edu/~allan/fluids/page7/PipeLength/pipe.html try for about 4500rpm-4800 torque peak, a 7.8-8.2 dcr, and these are the valve timeing overlap ranges that are most likely to work correctly trucks/good mileage towing 10-35 degs overlap daily driven low rpm performance 30-55degs overlap hot street performance 50-75 degs overlap oval track racing 70-95degs overlap dragster/comp eliminator engines 90-115 degs overlap but all engines will need the correct matching dcr for those overlap figures to correctly scavage the cylinders in the rpm ranges that apply to each engines use range for a 383 street strip engine that will be about a 210cc head,but the flow of the 190cc-195cc heads is close enought that the only real differance will be a slightly lower rpm range for the torque and power peak. a tunnel ram or stealth ram intake and about 11.1 CPR and a cam in the 240@.050-250@.050 intake duration range with about .600 lift and a 108-110 lsa as a good compromise for max hp but a slightly milder 230-240 duration @.050 lift and a slightly wider LSA in the 112-114 range will make the car much easier to drive, increase the torque rpm band significantly and only reduce peak hp slightly look at this dyno chart, its a 350 with a crower #00471 cam , it makes 530ft lbs of tq and would make 450hp easily if it did not have a restrictive exhaust

236/242-520/540 extreme roller cam you might also want to look at these heads http://www.worldcastings.com/docs/03catalog/motown.pdf (ALUMINUM ONLY) http://www.dartheads.com/P1_SS_HEAD_230.htm

" Anything I should consider before buying? " short answer, power pack heads make reasonable door stops "the question usually goes, hey, got a chance to buy fuelie heads for $300, is this a great deal or what?" thirty years ago FUELIE HEADS were the HOT TICKET but your dealing with heads that are thirty year old technology, they will most likey need at least a valve job,new valve guides and new springs and port work, by the time you put that much work and money in those heads youll have more than likely spent more money for worse results than buying the more modern heads that have not had 30 plus years of stress,corrosion,and bad valve jobs http://www.fastnuf.com/Headguide.html HERES AVERAGE FUELIE HEAD FLOW NUMBERS http://www.kendrick-auto.com/462_chevy_head.htm heres two comon performance cylinder heads that are available today measured on the same flow bench http://www.kendrick-auto.com/dart_cs_iron_eagle_215.htm http://www.kendrick-auto.com/brodix_track_i__cs.htm THE CAM AND CYLINDER HEADs are some of the MOST IMPORTANT PARTS ON YOUR ENGINE AS FAR AS DETERMINING YOUR HP/TQ POTENTIAL YES THE FUELIE HEADS ARE BETTER THAN MOST STOCK HEADS, YES THEY CAN BE PORTED BY EXPERTS AND MAKE GOOD HP,BUT BY TODAYS STANDARDS THEY ARE STILL LESS THAN IDEAL. EVEN THE COMON VORTEC TRUCK HEADS CAN EASILY OUT FLOW THEM, http://www.kendrick-auto.com/vortec_cs_gm_head.htm DO YOURSELF A HUGE FAVOR AND IF YOU SPEND MONEY ON ALMOST NO OTHER PARTS BUY GOOD HEADS, LOOK AT THESE ENGINE BUILDS http://www.ryanscarpage.50megs.com/combos1.html THE ONE THING YOULL FIND OUT IS HIGH HP ENGINES REQUIRE GOOD CYLINDER HEADS AND A MATCHING CAM, I CAN,T THINK OF A MUCH BIGGER OR MORE COMON MISTAKE THAT TRYING TO BUILD MAX PERFORMANCE WHILE RESTRICTING THE ENGINES POTENTIAL WITH STOCK HEADS a rough FORMULA/gauge to guess the hp POTENTIAL FROM THE CYLINDER HEADS FLOW NUMBERS is (.257 x flow at max cam lift x 8= potential max hp) so if you have 225cfm= about 462 hp if you have 260cfm= 535 hp now your highly unlikely to reach MAX HP POTENTIAL but the better heads will almost ALWAYS SHOW that 15% or better results. on a 400hp engine running fuelie heads that is likely to mean you would have had 460hp with the better heads (15% improvement) look over these heads ALPHABETICAL ORDER AFR BRODIX CANFIELD DART EDELBROCK G.M. PERFORMANCE PRO ACTION TRICKFLOW WORLD PRODUCTS heads they all have better heads a good set of cylinder heads makes or brakes your combo as far as the hp it produces, youll be doing yourself a huge favor to get the best heads you can possiably afford even if it requires waiting a few months, the iron eagle 215cc, trickflow 195cc,AFR 195cc , DART PRO 1 and MOTOWN 220cc ALUMINUM heads have all proven to make good hp if you take the time to match them to the correct displacement,cam tining and compression ratios

just some info theres two basic bore sizes, the 350 block with its 4"-4.060 bore and the 400 block with its 4.125-4.185 bore many people build 355s by just boreing the 350 .030 oversize with higher compression pistons,and are happy with that, the guys wanting more horsepower and torque build 383s by adding a 3.75" stroke crank, or a 396- 401 with a 3.875 crank and new higher compression pistons, you can make very good horsepower from that engine block and bore size. now if you upgrade to a 400 style block with its larger bore you could build a 377,you could reuse the 350s rods and crank, with bearing spacers in the 400 block with bigger pistons. But I don,t build many 377s anymore for one very simple reason, please follow the logic people build 383s to get the most potential power from that bore size and the 350 block they already have in their corvette for the least cost,for the best resulting power. but a 400 block with its bigger bore is not effectively getting its full potential with a 350 crank to build a 377 you need a 350 crank with a 3.48 stroke and a 400 block bored .030 oversized (4.155 bore x 3.48 stroke x 8= 377.48 displacement) if you already have the 4.155 bore block and you install a 3.75 stroke crank youll have a 406.77 displacement, if you install a 3.875 stroke crank thats a 420 displacement....... and considering youll make about 1.2-1.4 horsepower per cubic inch of displacement with identical parts and that the combination of the longer stroke and 29-43 EXTRA cubic inches of displacement provide a noticable increase in torque and horsepower, (similar peak horsepower but 30 to 60 ft lbs of TQ more is comon) and that the higher average rpm levels in the 377 tends to get into valve float much more easily... I find its just comon sence to build a 406-420 engine not a 377 570 HP 406ci AFR 210cc Competition Package 10.1 750 Carburator MSD Distributor @ 36° Timing Lunati Hyd. Roller Cams 242°-252° .560-.572 lift 112 Lobe Centers 1 7/8" Hedman Headers 500 HP 383ci AFR Street 190 Cyl. Heads 9.5 Holley 0-4779 750 cfm MSD Distributor 36° Timing Comp Cams 12-433-8 Hyd Roller Cam 1 3/4" Headers most of you will not exceed 450-470hp in your engines, so keep in mind that rods and rod bolts fail far more often then cranks, Id put the money you save buying a good cast crank into a set of (H) style rods with 7/16" rod bolts, a cast crank with good rods and rod bolts thats been ballanced and clearanced correctly should have ZERO PROBLEMS at your power level one piece of advice thou, its almost always best to buy the crank as part of a matched set of parts in a ROTATEING ASSEMBLY KIT and get a FLUIDAMPER harmonic ballancer and if possiable have the INTERNALLY BALLANCED STYLE KIT, as it has FAR LESS stress at high RPMS heres some places to look http://www.scatcrankshafts.com/ http://www.flatlanderracing.com (stroker kits) http://www.strokerkits.com/383.htm http://www.midwestmotorsportsinc.com/ http://www.competitionproducts.com/page88.html http://www.herbertperformance.com/ and also remember the cylinderheads, cam, and compression ratio must match your intended hp goals http://www.herbertperformance.com/ Phone (800) 444-7373 (I buy more kits from these guys , ask for LARRY ext 106) simply because they CUSTOM ASSEMBLE EVERY KIT PART BY PART so you get EXACTLY WHAT YOU ASK FOR,NOW THAT OF COURSE REQUIRES YOU TO THINK THRU YOUR PART LIST AND ASK FOR THE CORRECT MATCHING PARTS (heres what I comonly ask for in a 383 kit) be very specific as to the brand and part number of parts included in the kit if its important to you!they will try to save you money with cheap parts if you don,t get specific in your parts list! ITS YOUR FAULT NOT THEIRS IF YOU DON,T GET THE CORRECT PARTS ORDERED internally ballanced crank (cast or forged)(depends on hp level, 450hp or below go cast, forged is to some extent wasted money) MATCHING (H) style rods, set up for floating pins and main bearings that fit your block(350 size mains)(400 size mains) (H) style 5.7 or 6" rods with 7/16" bolts forged pistons for floating pins(MUST MATCH RODS and be .030-.060 oversize) with matching light weight pins and locks and be the correct cpr matching rings quality ballancer race quality flexplate ARP oil pump drive shaft have assembly ballanced either by them or locally

in many cases I think that the guys behind the counter are aflicted with (D.K.S.A.D.C.) ( DON,T KNOW S##T and DONT CARE.......comonly know as DUMB SHI$ DISEASE!) a fairly common disease that seems most comon among minimum wage jerks that can,t get another job! in most cases the quick cure is a trip to the local chevy dealer to purchase the correct dipstick,or the use of a tubing cutter to shorten the tube and a dremel to cut off and remark the extra long dip stick after carefully filling the oil pan and marking the correct oil level on that custom dip stick BTW if you hang around with those afflicted with DUMB SHI$ DISEASE! you could catch it, its best not to stay within 30-50 yards of those so afflicted, because its slightly contagious, it seems to be spread by listening to those prior victims

DO YOURSELF A BIG FAVOR buy these FIVE books, it will be the best money you ever spent, read them, and you will be miles ahead of the average guy. believe me youll save thousands of dollars and thousands of hours in wasted effort HOW TO BUILD THE SMALL BLOCK CHEVEROLET by LARRY ATHERTON&LARRY SCHREIB . HOW TO BUILD MAX PERFORMANCE CHEVY SMALL BLOCKS ON A BUDGET by DAVID VIZARD . JOHN LINGENFELTER on modifying small-block chevy engines how to build & modify CHEVROLET small-block V-8 CAMSHAFTS & VALVTRAINS BY DAVID VIZARD SMOKEY YUNICK,S POWER SECRETS THE DISPLACEMENT,CYLINDERHEAD FLOW and cam timing and compression ratio are the major factors in how well the basic combo will work, of these watch the compression ratio matches the cam timing, the larger the displacement the better and cylinderheads are one of the most important parts in the whole combo!

everyone I know with a TPI likes the low rpm (100rpm-4000rpm) torque but HATES the way the intake just hits a wall on air flow and power in the 4000-4500rpm range where no more airflow can be pulled thru those restrictive runners. basically the 350 or 383 short block is a great starting point but the STOCK or EVEN PORTED TPI intake and HEADS ARE SEVERELY AIRFLOW RESTRICTED I found this info and I figured you guys might like to look it over, now the first thing I want to point out is where the DATA came from. and KEEP IN MIND ITS REAR WHEEL HP AND The TPI INTAKE IN THE TEST consists of 58mm TB, fully ported plenum, AS&M largetube runners, and highly ported Edelbrock base WHICH MEANS ITS ALREADY MAKING AT LEAST 25HP-30HP MORE THAN A STOCK TPI INTAKE) link to c-4 stealthram http://www.eecis.udel.edu/~davis/z28/winter01/dyno/ The engine was basically the same,in all the test except for the intake manifold, consisting of a ZZ4 crate motor, AFR190 heads, LT4 HOT cam, and SLP 1-3/4" SS headers. Trans is a 700r4 with a Vigilante 2800 stall converter. The Engine Control Module (ECM) was a '92 TPI stock ECM (MAP/speed-density) with a modified EPROM. I HAVE GONE TRU AND WILL PICKED OUT THE IMPORTANT POINTS TO SAVE YOU TIME IN THE CHARTs AND GRAPHS ON THE SITE TPI engine.....283 PEAK rwhp @4800rpm peak AVG. TQ 291.5 AVG HP 269.5 miniram 303 PEAK rwhp @6200rpm peak AVG. TQ 285.8 AVG HP 269.1 IT LOST 29 HP at 3800 rpm and MADE 48 MORE HP THAN THE stock TPI at 6300 RPM stealth ram 342 PEAK rwhp @6400rpm AVG. TQ 319 AVG HP 300 it lost 28 hp at 3600 rpm BUT GAINED 66 HP AT 6600 RPM over the stock TPI 342 rear wheel hp is aproximatly equal to 427 flywheel HP FROM A 350 SBC ENGINE, figuring a 20% driveline loss rate. the use of a longer duration cam and only measureing PEAK HP would tend to benefit the miniram and STEALTH RAM intakes to a MUCH GREATER extent than the TPI, THATS HOW claims of gains of 100hp are made for some intake combos, while its TRUE that you can make in excess of a HUNDRED EXTRA hp at 6600rpms is due more to the TPI not being able to flow air (LOSSES) keep in mind that a LARGER ENGINE DISPLACEMENT WOULD BENEFIT EVEN MORE from the steathram link to c-4 stealthram[/b] since I SPENT YEARS RESEARCHING THIS SUBJECT! LET ME POINT OUT A FEW THINGS (1) heres the flow numbers (2)no matter WHAT PLENUM DESIGN YOU USE,your MAX AIRFLOW WILL BE LIMITED TO THE MOST RESTRICTIVE OF THE TWO,(RUNNERS OR BASE INTAKE) that YOU PUT IT ON and THATS THESE FLOW NUMBERS FROM MATCHED INTAKE AND RUNNERS Stock intake manifold with runner Stock....................198.72 cfm ACCEL................213.52 cfm Extrude/ACCEL....217.11 cfm Super Ram............220.67 cfm the stock TPI has a hard time flowing 230cfm even with minor port work, look here most of this info is right off the accel,holley,edelbrock, and TPIS sites, add a little math and the results become much clearer!!! GETTING YOUR Intake....... length ....... port in -- out Stock GM Base--- 6.375"------ 1.47"- 1.96x1.2 TPiS base------ -6.125"------ 1.75"- 2.09x1.28 Accel base----- -6.125"------ 1.75"- 2.09x1.28 Holley base------- 6†runner 2.3â€- 1.9â€x 1.23 (2.337 sq inches) Runners Stock TPI----- -- 7.250"------1.470" round(1.70 sq inchs) SLP ----------- - 6.625"------1.600" round (2.01 sq inchs) Accel LTR------- 6.625"------1.615" round (2.05 sq inchs) TPiS----------- 7.625"------1.660" round (2.168 sq inchs) Mini ram -----3.5†LT1 ----------3†Runners (measured individually) Stock....................203.17 cfm ACCEL................242.02 cfm Extrude/ACCEL...275.83 cfm Super Ram............289.18 cfm Intake manifold with 3/8 inch radiused intlet .............................222.45 cfm Holley stealth ram ………..275cfm Stock intake manifold with runner Stock....................198.72 cfm ACCEL................213.52 cfm Extrude/ACCEL....217.11 cfm Super Ram............220.67 cfm Holley stealth ram …..275cfm ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet.........251.51 cfm ACCEL Hi-Flow intake manifold with runner Stock....................215.83 cfm ACCEL................232.53 cfm Extrude/ACCEL....243.21 cfm Super Ram............240.24 cfm Extrude-Honed ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet ............................275.83 cfm Extrude-Honed ACCEL Hi-Flow intake manifold with ACCEL runner ............................266.94 cfm Edelbrock Performer RPM manifold (Stock)..................286.51 cfm Edelbrock Victor Jr. .............................275.24 cfm HOLLEY STEALTH RAM the HOLLEY STEALTH RAM FLOWS at 275cfm out of the box, and has the potential when matched to the correct heads and cam to totally out flow most other intakes available,can easily reach 300cfm with minor port work and costs much less Stock…………………………… 275cfm Ported…………………………..300cfm Runner lengths Stock tpi manifold 8†runners 11.25â€, cylinder head 6†total 25.25†Accel super ram manifold 8†runners 7†cylinder head 6†total 21†Holley stealth ram manifold 6.26††cylinder head 6†total 12.26†Edelbrock performer RPM runners 6††cylinder head 6†total 12†Edelbrock vic jr , runner length 5.5†††cylinder head 6†total 11.5†take the time to read the links http://www.gmhightechperformance.com/tech/0307htp_holleystealth/ http://www.eecis.udel.edu/~davis/z28/winter01/dyno/dyno021105/webpage021105.html GAINS OF 60hp PLUS have been reported on mildly reworked engines and Im sure on a full race style, or engine designed to use the extra air flow engine the results would be far greater http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=2119&prmenbr=361 compare that to a super ram at $1370 plus flows about 240cfm to 275cfm with SERIOUS port work http://www.thunderracing.com/index.cfm?fuseaction=subcategory&subcategoryid=1125#P2944[/url] HOLLEY STEALTH RAM (intake ,plenum,fuelrails, regulator) about $460-$520 to convert your TPI plus cost of small base HEI ignition and small parts flows 275cfm-300cfm with port work custom height stealthram to fit under corvette hoods,LINK when you look at the choices the upgrade to the HOLLEY STEALTH RAM GIVES YOU THE MOST FOR YOUR MONEY, just like a 4 barrel carb potentially out powers a 2 barrel carb on the engine years ago its the increased airflow potential of the newer EFI intakes that limits to a great extent the power your engine can make now, your ECU matches the fuel to the ENGINES AIR FLOW AND IT THE EFFECTIVELY USED AND AVAILABLE AIRFLOW THRU THE ENGINE THAT MAKES POWER theres no contradiction at all ,look closely, this FLOW DATA WAS TAKEN and compiled from several differant flow benchs so the data differs very slightly but REMAINS VERY CONSISTANT ,what it says is that the runners by themselfs flow better than the runners when attached to the manifold base and that the ACCELL RUNNERS AND BASE OUT FLOW THE STOCK RUNNERS AND BASE INTAKES WHEN THEY ARE COMBINED when I had a stock untouched TPI flow tested several years ago the flow from the ports measured with the throttle body mounted on the TPI was under 180cfm per port. Runners (measured individually) WITHOUT INTAKE Stock....................203.17 cfm ACCEL................242.02 cfm Stock intake manifold with runner Stock....................198.72 cfm ACCEL................213.52 cfm the bottom line is that the TPI is HIGHLY RESTRICTED and EVEN THE HIGH FLOW BASE AND INTAKES AVAILABLE WHILE VERY HELPFUL, REMAIN VERY RESTRICTIVE. the STEALTH RAM IS FAR LESS RESTRICTIVE intake, a set of AIR FLOW RESEARCH 190cc heads on a 383 11:1 shortblock with a cam like a crane #119661 or CROWER #00471 and a STEALTH RAM will produce a VERY GOOD HIGH TORQUE and HIGH hp ENGINE FOR A (Z), 470hp/500tq should EASILY BE AVAILABLE OR EXCEEDED if your looking for max hood clearance the STOCK HOLLEY STEALTH RAM is 10.25" tall from block to the top the CUSTOM STEALTH RAM is 9" tall and can be easily machined to only 8 5/8" tall (LESS THAN A STOCK TPI) link to c-4 stealthram

I just don,t think adjusting the valves without oil pressure and the block up to operating temp. is the best way either so.... how do you adjust valves at idle without the mess of oil getting all over the engine and headers HIT A FEW YARD SALES, SWAP MEETS UNTILL YOU FIND A DIRT CHEAP SET OF TALL CAST VALVE COVERS LIKE THESE, the CONDITION THEY ARE IN ,WITHIN REASONABLE LIMITS OF COURSE IS NOT THAT IMPORTANT you simply cut the ribbed center section out of the valve cover, and glue the synthetic valve cover gaskets on them in the normal location, when you go to adjust the valves you first remove the standard valve covers and install your VALVE ADJUSTMENT COVERS, they retain about 80%-90% of the oil that would normally be lost over the edge of the cylinder head while adjusting a running engine, they also catch much of the splashed oil, just leave a 1/4"-3/8" of the rolled top for strenth around the perimiter of the top surface. I bought my set for $10, they were old and slightly discolored but I could not care less! I took them home and used a drill and saber saw to remove the center ribbed area, theres several brands that are very similar in appearance, all will work! and Ive used them for over 25 years, if I remember correctly they are mickey thompson brand now if the lifters are hydrolic of course you just back the adjustment nuts off the rocker studs with a wrench, slowly until the rocker JUST starts clicking , then slowly tighten the nut just up to the point that the clicking stops then add 1/4 to 3/8 turn to preload the lifter and move to the next rocker and repeat, the only differance with solid lifters is you use a feeler gauge inserted between the valve tip and rocker after they click slightly,to measure the lash distance recomended on the cam spec. card (normally .016-.028 thousands) and you tighten them just to the point at idle that the clicking stops... then you remove the feeler gauge and move to the next rocker if your useing jam nuts dont forget to lock the allen key

DAVID, THE TEST WAS WITH A PORTED PLENUM/BASE/RUNNERS, not a STOCK PLENUM,ETC. http://www.eecis.udel.edu/~davis/z28/winter01/dyno/ "The TPI currently consists of 58mm TB, fully ported plenum, AS&M largetube runners, and highly ported Edelbrock base) " The engine was basically the same,in all the test except for the intake manifold, consisting of a ZZ4 crate motor, AFR190 heads, LT4 HOT cam, and SLP 1-3/4" SS headers. Trans is a 700r4 with a Vigilante 2800 stall converter. The Engine Control Module (ECM) was a '92 TPI stock ECM (MAP/speed-density) with a modified EPROM. I HAVE GONE TRU AND WILL PICKED OUT THE IMPORTANT POINTS TO SAVE YOU TIME IN THE CHARTs AND GRAPHS ON THE SITE TPI engine.....283 PEAK rwhp @4800rpm peak AVG. TQ 291.5 AVG HP 269.5 the stock TPI makes 245hp PEAK http://www.ifrance.com/accf-sprtcar/corvette/specs/91.html

read this article also http://www.gmhightechperformance.com/tech/0307htp_holleystealth/ when you look at the choices the upgrade to the HOLLEY STEALTH RAM GIVES YOU THE MOST FOR YOUR MONEY compare the airflow numbers CROSSFIRE INTAKE 190cfm per port runner (measured individually) TPI Runners (measured individually) Stock....................203.17 cfm ACCEL................242.02 cfm Extrude/ACCEL...275.83 cfm Super Ram (ported)............289.18 cfm Intake manifold with 3/8 inch radiused intlet .............................222.45 cfm Stock intake manifold with runner Stock....................198.72 cfm ACCEL................213.52 cfm Extrude/ACCEL....217.11 cfm Super Ram............220.67 cfm ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet.........251.51 cfm ACCEL Hi-Flow intake manifold with runner Stock....................215.83 cfm ACCEL................232.53 cfm Extrude/ACCEL....243.21 cfm Super Ram............240.24 cfm Extrude-Honed ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet ............................275.83 cfm Extrude-Honed ACCEL Hi-Flow intake manifold with ACCEL runner ............................266.94 cfm Edelbrock Performer RPM manifold (Stock)..................286.51 cfm Edelbrock Victor Jr. .............................275.24 cfm Runners (measured individually) HOLLEY STEALTH RAM Stock....................275 cfm HOLLEY STEALTH RAM ported..................298 cfm THE HOLLEY STEALTH RAM EFI INTAKE SYSTEM POTENTIALLY MAKES MORE TQ OVER A WIDER RPM RANGE AND SIMILAR or HIGHER PEAK HP THAN THE BEST OF THE OTHER CHOICES AVAILABLE AND WITH THE CUSTOM PLENUM IT FITS CORVETTES http://www.fasterdeals.com/garageindex.html 1985,1992,1996 vettes keep the rubber side down and the fiberglass off the guard rails

look over this site carefully, a CORRECTLY BUILT BUICK can easily make some serious hp http://www.taperformance.com/products.htm http://www.taperformance.com/newpage11.htm

a few things you should know [1] synthetic oil desolves that yellow 3m weatherstrip gasket adhesive than many guys use over a few months time so you cant use it to glue valve cover gaskets [2]you must use a o2 safe gasket cement like the BLACK RTV silicone cement and you must clean and degrease the cover with acetone or a similar solvent before glueing on the gasket to get the best retention [3]you need to allow at least a few hours to over night,depends mostly on temp. for that black silicone gasket cement to set up before installing the valve covers, and placeing them gasket side down on a table with a sheet of wax paper under them and a 20lb weight on top of each valve cover while the cement sets up is the best way to insure the gaskets stay correctly aligned on the valve covers perimeter [4]a light coat of (PAM) cooking spray on the lower gasket surface keeps them from sticking to the cylinder heads after installation [5] these gasket retaining rings add a great deal to the valve covers ability to firmly hold the gasket WITHOUT bending SHEET METAL VALVE COVERS OR CRACKING CAST ALUMINUM VALVE COVERS AND ARE WELL WORTH THE MINIMAL COST [6]doing it correctly the first time saves time and money http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=2207&prmenbr=361

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