Guest Anonymous Posted July 11, 2001 Share Posted July 11, 2001 ok im really trying to stay with my original unorthadox 283/287 but im also worried about not being able to find cylinder heads that will produce power on a sub 4 inch bore. i was set on using the edelbrock performer rpm heads nad intake etc. but just read that they cannot be used on anything less than a 4" bore. ! Ive seen the 305 torquer heads in PAW.. mixed feelings i guess, im just not too fond of any head for the 305. am i wrong in thinking this? 461/462 heads are supposedly good heads but will they be ok on a 283? ive looked around on the internet and havent been able to get a solid answer. im almost at the point of using the 283 crank i have with a small journal 327 and making an 302.. any input please! regarding the 302 where could i find 4" Bore pistons with a 1.8 inch compression height? i guess the goal is around 300-330 hp more would be great but i want to stay with the smaller displacement. thanks again Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 11, 2001 Share Posted July 11, 2001 How about finding a small journal (62-67) 327 Block or use a 350 block with bearing spacers (might have to make those out of 350 bearing shells). Then get some 302 pistons, or order ones with the correct compression height? Use the 283 crank and rods (replace with ARP bolts) and put the 302 pistons on it in the 327 or 350 block and you'd have the 302. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 11, 2001 Share Posted July 11, 2001 For pistons buy some replacement 302 z/28 pistons. They are forged! The dome can be milled down to get the right height. Or you can order some from JE, ROSS, etc and get any congiguration you like. Call Scogin Dickie. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted July 11, 2001 Share Posted July 11, 2001 I agree w/Bubf; buy forged pop-up's & have the domes milled. This would be a lot cheaper than milling the block, cylinder heads & possibly the intake manifold(?) if needed. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 12, 2001 Share Posted July 12, 2001 I am in the same boat. I have a 305 on the engine stand because that is what I had laying around and it is in good shape, low miles. Have the same problem though, hate the small bore and longer stroke, and the lack of selection of good heads. However, I really like the idea of using a smaller displacement V8, would love to build a high revving 302 or 327 but parts are hard to come by as you have found. Thinking of buying the PAW 327, that should do the trick eh? For now, probably just going to port the stock heads, get a good cam, carb, and intake, and stick it in. Later I can stick everything but the cam on a better engine. Sorry, no solution to your problem, just didn't want you to feel like the Lone Ranger. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 12, 2001 Share Posted July 12, 2001 I'm also seriously considering a 302 Chevy as my motor. I think the high revving ability of it is particularly appealing. I think you can use a 265 crank as well, by the way. If I'm not mistaken, the 283 is a small journal and the 265 is a large journal... Even if it only produces 300-350 horsepower, any motor that can rev to 6500-7000rpm is gonna be FUN AS HELL! My dream motor: -350 bowtie block -283 or 265 forged crank -302 pistons -rods? I don't know yet... -a fairly radical roller cam with roller rockers -one of those trick aftermarket fuel injection systems Anybody here ever owned a 302? Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted July 13, 2001 Share Posted July 13, 2001 I have a friend Richard that owns a full race Austin Healy with a wc/t5 and a DZ302 all forged, full roller. Good to the sky's the limit 8500 rpm's Im sure. What a terrific ride. Flat out awsome! Mike Quote Link to comment Share on other sites More sharing options...
SpeedRacer Posted July 13, 2001 Share Posted July 13, 2001 Do the 302 man - they are awesome mouse motors and rev like mad!! BTW, I think you will find that the TrickFlow 23 degree heads will work on a 283. TrickFlow Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 13, 2001 Share Posted July 13, 2001 FWIW A Speedvision program regarding the '69 Z28 with the solid lifter 302 stated that the factory recommended shift point was at 7400 rpm! They also stated that the motor was underrated (290 horse?) and the actual horsepower was closer to 400. If that is true it sounds like the engine for me! It was known as being "peaky" though, meaning not much low end torque. Just about right for a lightweight Z with 3.90 gears like mine. Decisions, decisions... Quote Link to comment Share on other sites More sharing options...
Guest Night_rider_383 Posted July 13, 2001 Share Posted July 13, 2001 Montara22... The 265 was a small journal engine like the 283, 1st gen 327's and 302's Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 13, 2001 Share Posted July 13, 2001 Another way to build a 327 these days is to take the more available 350 block (pre-86) and use a large journal 327 steel crank (68-69) or a 307 cast iron crank (same 3.25" stroke and main/rod bearing diameters match the 350 and large journal 327). Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 13, 2001 Share Posted July 13, 2001 thanks guys, ive been talking to the machine shop near by and he doesnt seem to know a lot about the smaller displacement v8s. its hard to get solid answers about what will work. id love to go to another machine shop but being on an island im a little limited. im thinking about just punching my 283 out to a 292 and using 461 heads with the 2.02 &1.60s does anyone know if it is definitely required to run a 4" bore with the 202 valves? THANKS! dan Quote Link to comment Share on other sites More sharing options...
Guest Night_rider_383 Posted July 13, 2001 Share Posted July 13, 2001 283z... Anyone thats into performance chevy engines will tell you thats a head DON'T for sure. 4'' bores are needed to clear 2.02''/1.60'' valves. Now you might be able to get a 4'' bore out of a 283. Alot of the 1962 and up 283 blocks was made on 327 tooling. That means these blocks can be safey bored .155'' over to a 4.030 bore. The most desirable 283's are the ones with a casting number of 3790721 cause this one was a 283 and a 327, They also was a thick wall engine and has a higher nickel content. These was put in alot of the chevy II's. Now let me make this clear not all 283's can be bored that much only the ones that was made on 327 tooling. Other 283's max over bore is .060''. If what you really want is a powerful high rever small journal then go for it bud. You could use a small journal 327 to do the job or if you want more rpm then use the small journal 327 block and a 283 or 265 crank. It would be hard to find a 327 that didnt need to be bored .030 over but still even at 4.030 bore useing a 3.00 stroke that gives u a 306.1 cid. Any good piston co. can make you good strong custom pistons at a fair price. I'm pretty sure if you wanted some of the best JE would be the brand to go with and i would think the price would be around $500-700 but there some of the strongest and lightest on the market. With that combo and forged 5.7'' rods, good roller cam, file fit molly rings, good intake, light stainless valves, light valve train, Good flowing heads with a good port job, alum roller rockers, etc. That engine could spin up high fast, Maybe redline at 8300 rpm or ever higher Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 13, 2001 Share Posted July 13, 2001 Night_rider_383- Thanks for the correction. I wasn't sure about that... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 13, 2001 Share Posted July 13, 2001 Depends on the output of the 302, but the short stroke motor will have less torque than one with a longer stroke. It will make peak horsepower at a higher RPM and will have a torque curve to match. Whether this is a factor in a T5's lifespan I'm not sure. I do know that a WC T5 is rated at 330 ft lbs of torque, and I don't think you'll be pushing that torque rating with a street short stroke 302 IMHO. Of course bang on it long enough even with less torque, and who knows? Regards, Lone Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 13, 2001 Share Posted July 13, 2001 I think you'd be o.k. with a WC T-5 if you didn't bang gears, power shift, etc. and didn't drag race with sticky huge tires. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted July 13, 2001 Share Posted July 13, 2001 Dan, I'm gonna kind of rattle off an idea or two & then I'll give you my slant of cyl.head's from what I've read. For starters, the 283 SBC/V8 has a rather large Piston Comp.Height of 1.800; have you considered using a 6" rod? With the SBC's Block Deck Height of 9.025"; take this figure & deduct half the 3.000" stroke of 1.5", a 6" rod & you'ld still have 1.520" flat tops for a piston comp.height: all this with a .005" Piston/Block Deck Clearance for squaring your block up(?). Now, bout your cylinder heads; surely you know there's more to cyl.heads than just the cyl.heads....such as, which camshaft you're going to use. (As he responds-Yes I know that & quit calling my Shirley!). When looking at Cyl.Heads you have to consider Volume, Mass & Velocity. The mass of the air is out of our control, usually, so we need to concentrate on the Volume of the Ports & at what Velocity the air will be flowing thru your engine....this entails Displacement of your engine & RPM's of that Displacement. Because you've mentioned the 283 & possibly the 302-I think its safe to assume you'ld like to build a "High Winder". So I'll assume a solid/definate 6500 rpm's for our hypothetical engine. My first question to you is, "What Compressions Ratio are you looking for? Race Gas or is this to be a daily driver to be ran on Pump Gas. Again I'll assume a daily driver & figure 9.5:1 Comp.Ratio for a 291/V8. This would mean that your final Cyl.Head Combustion Chamber (Final-means you've already considered Head Gasket Crushed Thickness, Piston Dish cc's/Dome cc's, Piston Deck to Block Deck Clearance cc's along with your Combustion Chamber cc's) would require a Final 70.33 cc Combustion Chamber. Now we have the Final Combustion Chamber; now we need to know what port flow is required for your 6500 rpms. This entails the Cyl.Head's Intake Port Entry, in sq.in's, as it is this port entry which is the main decider of your engine's peak power/rpms. You engine Displacement w/6500rpms indicates your port entry requirement of 1.52 sq.in's; this is rather small/easy to find with today's standards: I would shoot for a 1.8sq.in's to 2.0sq.in's intake port entry at the cylinder head-this will give you the best of both worlds & allow a better "Peak HP" pull at high rpm. The problem arises when you try to determine your HP needs. The airflow Velocity is hurt by smaller Intake Port CFM's of 160/170 even up to 180...thus requiring a CFM of 190cfm or greater to obtain the HP needs to get you to your 6500rpms. This is all good for high rpm needs but horrible for low rpm needs! A 190cfm intake port for your Displacment w/a Hydraulic Roller is good for up to 325hp-then your peak HP will begin to fall. This means you'll need a 200 to 220cfm cyl.head which would be good for 340 to 375hp (FWHP). Remember-for every give there is a take! This is a mathmatical law of "Inverse Proportions". In other words: a job will take longer to do if lesser men are available to do the job/likewise-the job is finished quicker if more men are available to do the job. You get somewhere quicker if you drive faster (usually)/likewise-it'll take longer to get there if you drive slower! Thus-you have to decide: do you want low rpm stability or do you want high rpm capability! "Lingenfelter" likes to use his Interport Relationship when deciding Cyl.Heads. That is, to divide the Exhaust Port CFM into the Intake Port CFM to obtain a percentage: such as 85/195=.44%. Further, Lingenfelter likes a cyl.head whose E/I% is around 75%-85%; but then he's pushing the 10K rpm limits also! "Ed Staffel" of Chevy Rat Motors (performance book) prefers to use the ratio created by obtaining the Intake Valve sq.in's by the Total Displacement per one Cylinder. So if you're building a 291/V8 you'ld divide your total displacement by 8 (#of cyl's) for 36.48. Then you'ld take your intake valve diameter 2.02 & square it then multiply it by .7854 like so: 2.02^2 x .7854 = 3.20 sq.in's. Now divide the Cylinder's total swept volume by the valve area's sq.in's like so: 36.48/3.20=11.4 ratio. If you begin using this technique you will begin to understand its relationship to a larger port engine -vs- small port engine; keeping in mind a larger port/larger valve will hurt airflow at lower rpm's & the engine may spit/sputter till it reaches it's target peak power. "David Vizard" of How to Build & Modify SBC Cyl.Heads" like to take the opposite approach to the intake valve & the Cyl.'s Total Swept Volume. Vizard like to see how many Sq.In's of Intake Valve area there are to each Cubiv.Inch of Displacement per cylinder...such as 3.20/36.48=.087 sq.in's per cu.in of cyl.displacement. Vizard also likes to take the CFM per the Cyl.Head Intake Port & divide the Total Cyl.Swept Volume into the Cyl.Head's Port CFM at max lift like so: lets say your cyl.head flows 220 CFM @ .500" lift: 220/36.48=6.03 CFM per Cu.In w/in one total Cyl.Swept Volume of Displacment. One more thing about the cam; using the above 9.5:1 Req.Comp.Ratio for a 291/V8 running on pump gas: you'ld need a camshaft whose advertised "Seat to Seat" Intake Valve Closing (taken at .0044") closed the intake valve at 46* ABDC. The Lift/Lobe Seperation angle will be yours to decide as this will be the determining factor of "how fast" you'ld want your engine to get there; in other words-do you want your rpm to rev quickly (peaky) or do you prefer its pull to be a little more "broad" of a rev. Hope I heldped & didnt confuse; good luck/keep us informed! Kevin, (Yea,Still an Inliner) [ July 13, 2001: Message edited by: Kevin Shasteen ] Quote Link to comment Share on other sites More sharing options...
SpeedRacer Posted July 14, 2001 Share Posted July 14, 2001 Needing a 4.00" bore for 2.02" intakes may be true for stock heads but I just checked the specs again on my TrickFlow 23 degree aluminum heads and it states 262 - 400 CID SBC. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 14, 2001 Share Posted July 14, 2001 Interesting, it might be because of the slightly off center stagger of the valves on the trick flow heads? Regards, Lone Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 14, 2001 Share Posted July 14, 2001 kevin,your absolutelty right about the kind of engine i want, in regards to making a 302 wouldnt it be alot easier to just use a regular 5.7" rod and use a 327 piston with a .125 dome on it? a 327 uses a compression height of 1.675 so wouldn the .125 dome put me right at the 1.800" desired compression height? also in regards to the intake volume i had a question for you.. why would such a large volume intake port (190-210cc) be required to get 375 hp out of a 302 if you can get 420 hp with the edelbrock rpm heads on a 350 when the rpm heads only use a 170 cc tract? just wondering? oh also to anyone who'd know what year camaro had the .62 overdrive? Quote Link to comment Share on other sites More sharing options...
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