57 Corvette heads

[Bruce B.]

Is this correct?
My information says that the 3740997 (pyramid symbol) heads are used on all engines except 283 HP. The 3731539 (smokestack symbol) heads are used only on the 283 HP engine.
In addition the valve sizes are all the same from head to head but there is a 7cc difference in chamber capacity, 359 = 57cc, 997 = 50cc.
All info will be appreciated.

[Doug F.]

Re: 57 Corvette heads

it's the other way around i believe

[Richard P.]

Re: 57 Corvette heads

Bruce,
My information(Chevrolet by the Numbers) shows#3731539 as the pyramid casting symbol used on 283HP and has 60.1122cc combustion chamber. Casting #3740997 has smokestack casting symbol used on all other engines and has 55.685cc combustion chamber. All valves are 1.72/1.50

[Barry H.]

Re: 57 Corvette heads

The 997 stovepipe heads have "a shrouded spark plug" smaller cc because they were used with flat top pistons. (used on all except 283 hp).
The 539 pyramid heads have a larger cc because they were used with domed pistons to achieve the higher comp ratio.
Valves were the same size, but the 283 hp, & possibly the 270 hp engines used lightened swirl polished valves, along with the "097 solid lifter Duntov Cam"
Barry Holmes #940