1957 283 power pak heads. 58cc in heads=9:5:1 compression. Aftermarket heads 64cc=lower compression. Do i keep heads for compression. Installing a mild cam and dual quad. Any guidance is appreciated
57’s have small valves. You can buy iron 58 cc chamber with 1.94’s if you search after market. Check out EQ replacement heads. On a 283 I would not go to a larger chamber without changing pistons. Good luck
From a cost stand point, if the power pak heads are bolt on ready, use them. If not, get some aftermarket heads that are. The cost to refurbish the power pak's will be more than a new pair, IMO.
They were run with dual WCFB's and the 270HP cam and ran great, why reinvent the wheel. Using those heads will also look traditional. Check out the Jr. stocker thread. Don't over carb it. Pat
I usually say, "it's really hard to build any kind of CR with these small bore/short stroke engines". Given that, I'd look for some casting number 601, 305 heads, with 53cc chambers, and install some 1.84 intake valves in them if they don't already have them. Next best would be the 416, 305 heads with 58cc chambers, and do the same modifications for the 601's. You'll also get hardened exhaust seats with the later heads. Use a Z-28 style spring set that can be had really cheap on that auction site we all know and love. Only drawback with the 305 heads, is the accessory holes most guys here don't want to see. I'd also have them surfaced, and use some steel shim head gaskets. You "might" get 9.5 CR that way; refer to the first sentence of this post. DART used to make a 49 cc chamber head, but you surely DON'T need the larger valves those heads usually have. I am Butch/56sedandelivery.
L98 Chevy heads [C4 Corvette] 58cc chamber 1.94" intake 1.50" exhaust And being aluminium , you could weld bosses on them to use early script rocker covers They are considered junk on High Perf 350+ engines but would almost be overkill on a little 283
I have 2 sets of the #416 305 heads that will work on the 283s and most definitely wake up a 327 for street use.....
Yup, depends what you're doing with the engine. If you want to build a neat looking old 283, you just gotta use the early heads. If you don't really care about building an early engine, then put the late model junk on it.
You folks must have expensive machine shops. I had 2 sets of double humps built. New guides, springs, hardened exhaust seats, seals and surfaced. One set got new valves the other just needed a valve job. 300-350 per set. And looks correct. Contemplating building a 283 next. Wouldn’t put a set of 305 heads on it for free. Had a set, traded em off. The power pack heads just have the look. But I’m not worried about out running anyone.
The 88 and newer C4 corvette TPI heads are 58cc chamber. [and D port exhausts] GM upped the compression because Alloy heads run cooler casting number 10088113 C4 Corvette Alloy LT1 heads are different [gen 2] 327 Chevys came out standard with 60cc 1.72" intake , 1.5" exhaust "power pack" heads. So a 305 Chevy 58cc head with 1.84" Intake and 1.5" exhaust would be a cheap way to upgrade to hardened valve seats [and larger intake valves]
I think the main key here is do you want a period correct appearance that you may have to have a bit more done to the heads (hardened seats) to run what we call gas now or are you willing to give up the look to run those later and not period correct heads that are simpler to get some power out of and possibly less expensive. It's your ball, your game and your money. My first born and I stuck a 307 together with power pack heads, Edelbrock performer and a mid 70's Z28 cam that I picked up at the Portland swapmeet with the lifters marked with the lobe numbers packed in an egg carton for 25.00 and that bugger surprised a lot of would be fast cars in short street races. It would run all day at 70 and up on the freeway and pull 16 mpg too. With the right combination the heads work fine.
Its seems everyones opinion is keep the heads. Ok. Will i have a clearance problem with cam with a lift of .480? I've read something about rocker arms hitting top of inside valve cover on factory set up. By the way, not concerned about period correct look. Thank you for all the advice.
If you don't care about how it looks, then put newer heads on it. Might as well bump up the cubic inches, too....that's where you'll get real performance gains
I'll be darned, thought they were just an Al version of iron heads, are they center bolt too? Or perimeter? I'm pretty sure they use the pre-85/6 center intake bolt angles, OP might be able to pull it off okay.
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