Big block heads question

[pigpen]

I have two sets of heads and both are 452 castings. One set is off a 74 C-body and the other set is off a 78 truck. The only differance I can see is the 78 heads use the smaller 5/8" spark plugs. Any other differences? One set better than the other? Anybody know the stock valve size of the 74 era heads? I havent pulled them off yet. Thanks:tats:

Oh Yea, Another question. I have a chance to pick up a set of factory pistons from a 70' 440. 9.7:1 engine. Would they be forged or cast? Thanks again

 

[v8440]

In all likelihood, the heads are very similar except for the sparkplugs. Both will have hardened exhaust valve seats. Best thing to do is cc a chamber or two on each, and compare to see if there's any large difference.

On the pistons, they will be cast. However, if you can get them cheap and they're in good shape, they would be one way to bump up power in a later model shortblock. The '70 pistons will have a higher compression height, so they won't be as far down in the bore at TDC as later model pistons would be. Honestly, better yet would be a set of cheap pistons like some trw hypereutectics that come all the way to the deck surface of the block. With those you'd get the benefit of MUCH lighter pistons-light enough to require drilling a little material out of the crank to balance it. If you're willing to do this, you'll see more torque, hp, AND gas mileage. There really is no downside to getting rid of the abysmal compression ratio of the stock engine.