Ive scored a 57 283 2BBL thats had a stock rebuild with a dual exhaust. Its backed by a PG and a 3.36:1 rear. Done a search already and read most of the 283 posts (good info) but Im just wondering if someone can tell me how much can be shaved off the 283 2BBL heads to bump the CR to at least 9.00:1 (or more) from a stock 8.5:1. The intention is to increase efficiency, TQ and HP by adding a 57 cast intake with a rebuilt Rochester 4 GC 4BBL (have both) and add an nice cam to make use of the hike in CR and for a nice sounds, but nothing too lumpy or loud; just a nice little lope so you know its not stock. How much can come off the heads to bump CR and avoid valve to piston issues with a .450"-.460" max lift hyd cam? Any cam suggestions? This is for a 57 wagon. Really interested to know, been a small block MoPAr man for too long hehe... Rat
my 2 cents: i'm not a fan of milling heads on a SBC for compression..it can be done , but sometimes opens up a can of worms. is there any chance of you finding the `57 4BBL heads? that would give you 9.5 to 1
I'm with 36-3 window. Anything you mill off the heads will have to be milled off the intake manifold. Anything you do can't be undone making the parts almost worthless for trade/barter at a later date. Only my .02
I'll chime in on the other end...typically, I'm also not in favor of milling heads to raise compression. However, '57 2bbl heads are nothing special. You could swap to later 305ci heads, but that gives you the accessory mounting holes, which you probably don't want, as it blows the period look of the engine. If you've got a stock 8.5:1cr, verify that it truely IS 8.5...I've been told rebuild pistons often are lower CR than advertised. You shouldn't have to take very much off the heads to bump the compression up only half a point. If it were mine and I was going this route, I'd look really hard at bumping it up a full point, to 9.5:1. Still runs on pump gas, little more pop. If that gives you any piston-to-valve issues, the cheap fix is ****erfly cutting the piston domes. Another idea to consider is 1.6 stamped rockers, for a little more from your existing cam. With shaving your heads, you're looking at: dis***embling the heads completely Hot tanking them Machining You'll be shortening the distance from the rocker to the lifter, so you'll need new pushrods Other option would be to swap the cost of machining the heads (and possibly the intake manifold) for the cost of new pistons with the compression ratio you want. I like the idea behind your engine. Good, solid, subtle plan. -Brad
I would also run a MR. GASKET head steel shim gasket, .020 thickness will increase your compression. That will get you there.
i was told by an engine builder that you could mill your heads enough to bump your compression ration by .5, without having to modify the intake
Ok every one is against it but we used to knock .010 off 'em all the time. And you don't have to mill the intake with the small slice. If the heads have been faced more than once they are probably close to that anyway.
Hate to ***** up the thread, but I also have a 57 283 backed by a PG. I was wondering if the early 60's powerpack heads would make much of a difference on this motor? I just picked up a tri power setup for it which hasnt gone on yet.
Thanx for the info guys, much appreciated. I had thought of using the steel shim gaskets; at around .020 crushed, that should give me a little more pop I agree. Done a scope around which cam will suit my needs and came up with two grinds I thibnk might be the go. One is a Crane 272H 10 and the other is Comp Cams CS268H-10. Both grinds will work well will 9-1+ CR, stock convertors, the V ntake anf the 3.36:1 rear end i have. Durations @.050 for both came are close around the 218 deg with around .450" lift. Scheider, Isky and Lunati also make similar grinds? Anyone used any of these csms in a similar application and how did they perform ? Keep the info a comin !! Rat Snyone used these cams?
Frank, I know this is about upping the C.R., but perhaps the best thing you could do to improve the performance of your wagon would be to toss the 'glide with its 1.7:1 first ratio, and install a T350. A 3:1 first, 1.7 ish second, would do more for off the line performance that any cam shaft. I speak with a little experience on this matter - I once had a 307 + 0.060" and a TQ30 cam, a C.I. four barrel manifold and a Quadrajet in my 54 more door. It had an aluminium P.G. A bit of stall, Manual valve body, big clutches, shift kit, and a 3.55:1 8". it took a bit to get it moving, but once you were there it fair flew! Driveability would have been much better with a shorter first gear. I've got nothing against a C.i. 'glide, I ran one in the 54 whe I re-installed the original six, and I keep tripping over one in the shed today. If my back continues to play up, **** I might have to get rid of the Packard 3 speed, and wack in the 'glide or a T350!!! A HQ gearbox cross-member, bolted into the 57, and drilling 2 new holes for the Starter Motor, and Bob's your Uncle!!! Whatever you do with the cam, if you use the 'glide, you'll need a cam that "comes in" early to give it the best performance off the line rather than at 60 MPH. Earlier rather than later. My 2cents - you judge how well I've spent it.
Hey SB, thanx for the 2c lol !! I hear what you are saying but Im not afetr after an off the line burner nor a top end suicide machine !! Just something that sounds nice, looks totally traditional in the eng bay and is uncomplicated. I hear you on the cam choice for the Glide...makes total sense. That means, std unleaded, no hi stall convertors, headers or any of that stuff. Lets not forget a small cube 283 and Glide in a fairly hi geared and heavy ride isn't gonna fly and that not what I'm looking for. I'd like to stick with the Glide for now, if it throws in the towel down the track then a TH 350 might be the go. Rat
Maybe talk to Wade Cams, they seem to know a fair bit. I'll be trying one of their XU-1 type cam profiles for a street cam for my coupe.
So Frank we can ***ume no longer, new ride!!!! What about a t700? Or is the drag/street racer in you hanging onto the glide for future purposes???? Best of both worlds and this IS to be a driver yeah? Can't help you on the other stuff, never played with them chevy things......
Those little motors love to rev, the P.G. holds em back, badly! Takes a 327 or 348 minimum to overcome the lack of a first gear. TH350 has all of the dependability in the world without the excess m*** of a TH400. Since you are keeping the Glide, you better keep the cam MILD, that is unless it's in a 1700# T bucket.
Can't say I know about the aftermarket cams, but the GM 327/340 hp juice cam was perfect for street/midrange and a sweet sound.
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