Hello All, I picked up a vintage 283 which was a drag motor. It has 30 over high compression pistons, 2182 cam, heavy duty early connecting rods, steel crank. I have new head studs, main studs, windage tray etc. One cylinder was rusty which some of you may have seen in my other thread. I had cleaned up the block and painted it, but the rusted cylinder kept weighing on my mind. I will save the block for a 60 over build. I was able to find another 30 over block (on the piece of plywood in pics), was machined then not stored right so it rusted, brought to my friend's machine shop and we cleaned it up, should work well for my budget build. It all spec'd out great. I did a similar low buck build before and went deep twelves. I will run a tunnel ram on it and am really going for a mid 60's look. I have a Super T10 and a bunch of other good parts to go on it, Hurst front mount for the 283 etc. I plan to drop it in a Double A frame which will gk under my 27 T Coupe once I start on it or if I find a good Gasser candidate. I have some later heads, smog heads really but are nicely ported and have 1.94's which will work well on this motor. I have several other pairs of heads, Fuelies etc but the smogs with 76 cc chambers may be a good idea to knock the compression down a bit. I have various rockers but may even go with stamped steel to keep the vintage feel as much as possible. Tim
interesting, one of my buddies is building a 283 similar for a 57 chevy wagon. I have one under the bench. like to know how it turns out.
Using 76cc heads and 13:1 pistons sounds ass-backwards to me. Get rid of the pistons, supercharge it; or get rid of pistons and heads, get flat-top pistons and small-chamber heads.
If you are after a mid-60s look your choices of era correct tunnel rams are limited. Look for an Edelbrock TR-1, similar to my T bucket.
It sounds like the OP is doing the very traditional "using up the crap I have laying around" method of engine building. So buying new anything other than gaskets it out of the question.
I hate to throw cold water on it, but it’s almost impossible to get that much compression out if a 283 without a lot of milling. The pistons I have in my 265 are taller than those and we are barely squeaking out at 11.8:1 with 64cc . Get a clay mold of the dome and cc it. Then get online with a compression calculator. If you use the 76cc chambered heads it will be a pretty low compression ratio. I love 265’s and 283’s. I say build it.
Yeah who knows what the comp will be, I will check it out with my friend he is a machinist. For this build I am going with what I have laying around.
Re: Piston dome ccs: Wrap a piece of masking tape around the piston such that it sticks up past the dome to create a little "pool" and pour it full of plaster. Then cc the plaster "dish" the dome made in the plaster. WFM
I should mention that you need to take steps to keep the bottom of the TR-1 plenum from filling up with raw fuel. Some fill the lower half, I added bleeds to bleed off the accumulated fuel.
882's, there better options, but if you already have these - ported - in good condition, they'll run plenty of air for a 283. These were one of the go-to heads for years in circle track on factory iron head classes. Agree with cc'ing heads and piston tops to see what youre true compression is. Assuming the 2182 cam is this one? 3972178, 3972182, 12364054 1970 Z28 350 - 360 hp Lift .459/.485 Dur @ .050 242/254 LSA 116 If your compression is over 10.5 or 11 to one and needs race gas anyway - I'd swap the cam out to something NASTY. Cool build, use up the parts you have and make a strong runner.
I certainly can understand the use what parts you have philosophy. But I agree with 55Blackie that for better performance you want small chambers and a flat-top piston. Keep quench tight and get good turbulence in the chamber pushing against the nice flat piston surface. But given what you have, I think the large chambers will defeat some of your goals for a strong running 283, unless one goal is to lower compression to run pump gas. Completely agree with several previous replies to cc both the pistons and the heads and really figure out what you have. You may want to cut the heads a little if you can to reduce chamber and increase quench. What cam specs?
Why not take it out to 4 inches? You will have quite a few choices for pistons and it will easily wind to 7500-8000 RPM. And you can run the 2.02 valves. Routinely done in the late '50s and '60s.
If you're considering boring the block .125, you better have it sonic tested first. You might have junkyard, throw-away parts, but machine work isn't cheap. Even if you provide the labor, I hope your time is worth something to you, if not to others.
I can't believe that 76cc heads were used on any SBC for any kind of racing. There were/are other iron heads/w smaller chambers that were/are readily available. It makes no sense to use those heads on any SBC w/o forced induction. "Dur @ .050 242/254" is way too much duration for a 283, which is 67 cu. in. smaller than a 350, for street use. An LSA of 116 on a carbureted engine w/o forced induction doesn't make sense either, unless you're talking about a small cam for an emissions friendly engine/w EFI.
I don't have to convince you to believe - it was reality. Iron head claimer motors around me went to 882's versus double humps with the largest dome that could be crammed in them. I used to sell all the 882s to a local builder who'd throw in 2.02s port them all the same and had a row of sbc's ready for race season
Fun thread, if the short block is locked in with dome pistons, see what heads gives you the best targeted compression ratio, most efficient chamber and flows the best. If youre trying to run pump gas, iron head / dome pistons is the most likely combo to cause detonation issues. CC'ing the dome as assembled will tell where you're at.
Those Jahn’s pistons are sand cast, heavy and will probably need .006-.008 piston to wall. If you are committed to using them I’d look inside the crown and if the dome is solid consider cutting them down to gain some CC’s and lower the compression. Even if they are not completely solid you may still be able to cut them a bit. For a cam I’d go a lot milder for a 283 than that ‘182 grind, you want it to start pulling closer to off idle and lots of duration won’t help with that. You mentioned having main studs, do you just mean the GM main bolts with the integral stud for the windage tray or do you have actual main studs. If they are main studs you will likely need a line hone. Studs have different clamping forces and will affect the main bores.
Check this out: chevelles.com/threads/76-to-53cc-heads-what-will-cr-be.199274/ These guys went from 76cc heads to 53-58cc on their 350s. After reading it, I don't think you'll want to use 76cc heads on your 283.
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