dr_hunt

I have never heard of that but then again you learn something new everyday. You could calculate the cfm very easily based on rpm and displacement. You need a vacuum gauge hooked to manifold vacuum and check it at idle and part throttle. The powervalve that you have will open at 8.5 inches of vacuum and add fuel. if it has a stumble and you get low vacuum at part throttle then perhaps a higher number power valve like a 9.5 or 10 will help. I belive that they make them all the way to 11 or 11.5

sounds like a vacuum leak. carb base, intake, vacuum line, vacuum ports, check it all over good.

depends on the pistons, probably close to that with flat tops. I'd guess 11's but I might be wrong. Your biggest HP gain is with heads or NOS, Heads are the better way to go in the long run IMHO.

It's not speed, it's time, 11's require a cage, unless it's a convertible. I don't know how much they'll handle without twisting. I'd bet you'll be testing the HP output all the time!!

Jap, how'd you end up polishing the roof with asphalt? I'd venture to say you in the 730HP range at the crank, and around 600+ to the wheels. Did you get a matching intake with the heads?

Cool. Went to Manzanita racing IMCA and Late model. Ken Schrader (sp?) was there driving a "house" car for dirtworks. He did well and had 5 engines claimed by the end of the weekend all for $1000 each. Bet they lost over 50K in engines alone just to have fun.

Ok, checked the file, bow tie block, Sonny Bryant crank (3.75 stroke odd fire), 6 inch carillo's, JE pistons 13:1, Chevrolet Aluminum 18 degree heads CNC'd by Brodix. Custom roller from Crower, .704/.670, 800 holley by C&S, chevrolet race intake, made 523HP/440TQ peak numbers all NA.

I'm assuming that this is a new balancer that was never installed?... Or, is the crank new?... Either way, what does the crank snout measure and what does the inside of the balancer measure? There are threads in the crank that don't normally get used, but... Well, I hope you don't end up having to send it to a machine shop to get it redrilled deeper or larger, both can be done.

The vacuum pulloffs are available at your parts store like napa, kind of pricey, 35 to 45 apiece, maybe more now, it's been awhile since I bought any. The choke linkage or duct is a gm kind of thing. Better yet is to find a later qjet that has an electric choke they work much better than the hot air ones. Also with the hot air you have to have the early manifold that accepts the hot air piping that fits in the heat cross over portion of the manifold. With the electric choke, wire it to the alternator output. This way if the engine dies for some reason the choke doesn't continue to release like it would if it were connected to a switched 12V source.

Magnum what's your definition of streetable and how did you come up with that handle? My definition of streetable is way warped and completely unrealistic to most folks, but I want to live with no regrets and I built my first SBC at 14 years of age and I used silicone on the head gaskets cause I didn't know squat and I couldn't see how it would seal the water running from the block to the heads, but it worked anyway despite me. I don't think I mentioned that word streetable, I'm simply talking capability not practicality, and personal experience with 7 race v-6's on the dyno and on the track. I'm not sure what DD has for heads, probably really need an airflow file to get some good numbers but try pro ported wedge heads, solid roller.650 to .700 lift, 13 to 14 comp, single plane manifold, 800 cfm carb on alky and see what you come up with, then stroke it alittle and see what happens, pretty amazing. Play with carb selection, cam selection if you have some numbers cause they are the same as with any sbc. I'll dig through my records and see what combo's I have. It would be neat to see 4.3L 280z whip some v8 although I grant you he'll have to pack a lunch. Some circle track guys run them because of class, some because they get a weight break and probably more importantly because nobody claims the engines. Practicality doesn't seem to fit hybrid z's or it seems they wouldn't exist. Your entirely correct it is easier to achieve more HP with more cu in's, generally cheaper, but it isn't free, just available with more cubes like stroking and all of mine were stroked since I had to buy cranks anyway. 4.3L 280z is IMHO the purest essence of hybrid z, something different, unique in it's creator's own way. He's daring and my hat is off to him. And how did you come up with that handle?

There's nothing like the complete drivability of a perfectly tuned carb, whether it's for street or race. I'd venture to say that if somebody was willing to try one, then they'd never buy anything else. This of course is just my opinion and is based on the several C&S aerosol billet carb's that I own. I'd never go back to a box stock holley except to cruise the local drive in on gas rather than alky. This guy seems to know what's happening, I don't, so I'll leave it up to the experts, I do know that factory holley, even holley HP's, leave alot to be desired when compared to a custom built and massaged carb.

Well, I must of been mistaken, I though one of your pic's said sb2 on it. What kind of tq and hp you figuring it makes? I'd really like to have a 2 inch set of headers. I know that you can run sb2 heads on any sbc block but you have to run the cam, offset lifters and offset rockers to make it work. Seems it would be better to run the new sb2 block that has repositioned lifter bores. I watched a 4-7 swap engine on the dyno the other week. It was run with standard cam first, then the 4-7 swap. Torque and HP were up about 14 each, then engine seemed smoother throughout the rpm range especially in the higher r's.

I don't know, I've always used brass, but they don't last very long. When you find out if the composite will work and lasts longer, let us know.

Jap tin, I've seen pictures of your sb2.2 and car, really f'n awesome, been thinking about doing that as an option but there's not any running around here yet except for the Unsers, what are the particulars on the SB2.2, 50mm cam, Roller cam brgs?, raised location?, Cranks?, Deck height? Heads? Valve train? It's a 4-7 swap on the firing order as well isn't it? Who made your headers or did you do them yourself? Oil pans? Timing covers? Intakes?

The 4.3 is easily capable of 500 HP naturally aspirated. Chevrolet makes aluminum race heads, saw some on ebay the other day ported that went for $450 for the set. Standard 350 rods and pistons, that is correct. Look on ebay for some eagle, manley, or carillo 6 inch rods, even broken sets, they go cheap, pistons too. Vortec heads work well. Responds the same as a 350 to cam changes so choose cam patterns just like any SBC. The 93 and later 4.3's had balance shafts, stay away from those. If you have unlimited funds they make billet cranks for the 4.3 also. Something to ponder, oil in the combustion chamber contributes to detonation, ring seal is vital to optimum HP and TQ. Is it really worth it not to bore and hone with deck plates and mains torqued to get a really good round cylinder so you don't have oil consumption, smoke, and less than optimum power? I'm not saying it won't work just honing and putting some rings in, but why not do it right, make it last longer and run better than a half a#$ job.

If it's from a c60 truck then it will be 4 bolt and it will have a steel crank. The heads are special truck heads which take special brackets and larger diameter bolts, so you probably won't want those, no real performance heads on truck motors. The short block will have the good rods as well. Good buy.

I've been running alcohol for years, maintenance is the key, draining fuel lines, disassembling carbs, spraying penetrating oil into the fuel pump and draining the tank is all that is required. Alcohol is not corrosive it's the water it attracts since it is hydroponic. Definately not for the daily driver, however on a carbed system all I do is change carbs, from gas to alky or visa versa depending on what I'm doing. Cruising Sonic with a 700HP car attracts alot of attention from both the wanna be hotrods and Lt Fuzz. You pick up an easy 50HP and 50TQ with alky, usually more, and variations in weather conditions don't have much of an effect on tuning as is with gas. It's kind of like a shot of NOS, plus the engines runs soooooooooo much cooler which is why I run it for ultra high HP engines, avoid overheating problems. Turbo system should be well suited for alky, especially EFI, even with super large injectors should handle the conversion from gas to alky and back with the change of a calibration map easy enough. Budget isn't really an issue, engines run 8K in long block form with the best of everything like Carillo, JE, Callies, Dart block, roller cam, AFR Heads, etc. Figure turbo and FI another 8K. I'm not serious about racing with John Force, but I'd like to see some 9's and 8's. 9's on motor, 8's Forced induction. John's a nice guy though. The georgia SEZS is too far, should have the z running next month and planning on Phoenix in Feb 05 and of course Albuquerque all year since it's basically my home track. Guy here has a '71 240 with minor rust, hail damage for $400, runs, has SU carbs, 4 speed. If anyone is interested I'll take pic's. Thanks for the info, search, search, search.

Well, I guess I'm just a stickler for getting it absolutely spot on every time I build an engine, I'd rather not have "issues" to deal with, especially with customers, and I afford myself the same. One thing that really bugs me is that there seems to be so many members relying on someone else to build an engine and they fall victim to people who don't know what they are doing in the first place. When I was in my teens and twenties I'd only dream of these types of cars due to monetary issues when I worked in a engine machine shop, now money isn't as much of an issue, but time to do it all is, since it interferes with making the money to do it. I've done several blown alky injected engines for boats and drag cars, so I want to do a twin turbo FI engine just to do it, but I was thinking of around 1200HP at the crank 30 psi boost on alky or maybe 20 psi on gas, I'd use my Monte SS as the test bed for that engine which is scheduled for completion July 2005. If that works like I want it to, then I want to do one for my boys z. He's only 10, so I have to drive it until he turns 16, lucky me! You know I don't think he really appreciates what I'm doing, but at least I do.... I think the "drivability" aspect is what is so appealing. I have to remember that a 90 something inch wheelbase car can only effectively handle so much HP. 600 Forced induction is an easily achievable goal with todays heads, my boys NA 357 sbc engine made 650HP on alky already, just got the engine and PG trans installed in the Z this weekend, have a few loose ends to tie up, like fuel lines, shift linkage, exhaust, wiring MSD boxes, delay box, etc. It'll be interesting to see what it can hook up, which is what it's all about. His 260z has 9 inch ford with ladder bars, detroit locker and coilovers so strength isn't an issue, however since the wheel tubs are small, about all we can fit is a 10x29.5x15 slick in it. We bought the car like that so we may have to redo the backhalf since it all looks basically stock now and backhalf and tub it for real meat inside the stock fenders. All we did was install 10 point cage, and now that the engine and trans are in, I'm going to make it a 12 point cage. I'd post pic's but I don't know how yet or even if I can. I like the cruise to the drive-in scenario, can't hardly wait, docile 600HP on tap, this rates with sex and if you tell my girlfriend, I'll swear your a liar!! I'll check on the miniram, is that the ACCEL system?? Haltech and TechIII must be two different systems, I'll see what I come up with, Thanks, David

Yup, it's amazing how easy it is to break the threaded insert. I had my machinist make me two out of tool steel. You really have to watch and "feel" it for the slightest resistance or it'll break. Also put some silicone sealer on the shaft and keyway so it won't seep oil over time. David

They didn't have "vortec" heads in the '70's. They are the open chaber vette head, standard issue 2.02 int. and 1.6 exh. not 1.5 exh. unless it has had seats installed, nothing special except to a person restoring a 'vette. By standard issue I mean that they have no special performance value over even the '70 through '72 64 cc head. Things to look for are cracks, low valve seat height, stripped holes. If they look good I'd advertise them in a 'vette forum. The crane roller looks like it might be a 112 lobe center 234 duration at .050 street roller, probably under .500 lift according to this old crane book I have.

Yup, it'll fit. There is a site called Barkley racing, he has a z that's named ratzun. Used to run low 9's in Kansas. I think this question has been asked before and I believe there is one or two other guys in this forum running big blocks. Other than that I dont' know much about any parts availability to convert to a BBC. For the SBC and SBF there is ton's of stuff. I believe the SBC is the most popular route.

Quicker 240 I was thinking of FI on my next engine with twin turbo's. Mike set me up with a guy who makes exhaust for such. As far as the FI goes, what made you go with Proflo and if you had to do it all over again what would you use? Also, come by sometime and I'll install a sleeve in a junk block and show you how much it makes the adjacent cylinders out of round, typically it's .002, sometimes as much as .004 or as little as .001, but you can't put an interference fit sleeve in a block without some distortion. They used to make a glue in sleeve that used the same technology as the space shuttle that had the glue on tiles on the exterior. Supposed to handle the heat. They quit making that though and I never had any problem with those and they were the only distortion free sleeve I have ever installed. In the old days I used to sleeve all 8 cylinders on 400's in sprint car engines just to save a block, but now they have better aftermarket blocks than production and for the money they are the way to go for high HP foundations.

Don't sleeve it and slap it together. If you sleeve it it will distort the adjacent cylinders requiring rehone with deck plates to get it round again and you will end up with excessive piston to wall clearance which contributes to oil consumption, ring blow by and loss of power. Your local machine shop probably already told you all that anyway. You are going the right direction, let somebody else sleeve it and slap it together. S*#T Happens!

HEI's require a full 12 volts, no resister no way, no how!

The stated rpm range by the cam manufacturer is a guideline, not an actual rpm range that your engine will "pull" in and it assumes alot of things, like proper heads, valve size, intake, carburation, compression, header size, timing, elevation, all of which are "optimal". Solid roller is going to make more power and torque end of story due to faster ramp speeds. I run a solid roller in my 9:1 454 in my jet boat on pump gas. I wouldn't worry so much about lift, but getting the duration above 245 IMHO. I mean you have a 3500 converter, which is more of a race converter, so you ideally want peak torque around 4-4500 rpm which should land you somewhere around 250 duration at .050 to achieve that. If you have peak torque about 500 rpm above your stall speed you'll stall the converter better and within feet of launch you'll be in your peak torque. Just a thought, If you have traction issues, then 1000 rpm above stall may even be better, then it doesn't "hit" right away and the launch is "softer". You'll find that valve timing events are far more critical to making torque than just lift and duration numbers and you can tailor them to match the vehicle dynamics and get the power when and where you need it in the rpm range. the critical range is normally at the launch for light weight traction problem prone cars anyway. This is why the computer age is influencing cam design so much. All of the cam manufacturers use computers to model all aspects of camshafts and valve train, from dynamics to engine modeling software. Try the same like DD2000 or something similar. They are not perfect but when you are changing just the camshaft values you can see how that affects TQ and HP, so in a sense you are comparing apples to apples since everything else stays the same. This assumes that you input actual values as you have them for your car, not what you wish they were. EBAY, EBAY, EBAY! If you watch things, you can score a roller cam, springs, lifters and pushrods for under $500 and that is for NIB items. Sell your heads on EBAY, put another $500 with it and buy a set of AFR 210's if you already have stud girdles, buy AFR 220's or 227's if you don't, since they take offset girdles. AFR's with roller springs are good to .670 lift. With a 3500 stall converter, you don't have issues with loss of torque below 2500 rpm so it won't matter. Instead, you'll pick up 2 to 3 tenths with the bigger heads and another 1 or 2 tenths with better cam, switch to Alky and you'll pick up yet another 5 tenths and 5 mph on the top. Spray on top of the alky and your test the limits of the bottom end and balloon your converter. They have a NOS system for alky that is guaranteed to make a 700RWHP gain!!!