I have a 1982 z28 on which I am looking to do some improvements to the engine which is still the 305. I have been doing some research and it seems the TPI cylinder head combustion chamber was improved over the smog heads that were available prior. However, I already have intake manifolds for the older style bolt pattern and I was wondering if the TPI heads could be converted? Another factor I have picked up is that the 85 TPI still had the older bolt pattern and I was wanting to confirm this fact. If that is true does it have the same combustion chamber on it as the later heads?

Any response is greatly appreciated and thank you for your consideration.

Two center intake holes on the 87-92 heads are at slightly different angle than old style. What most do is oval out the intake manifold holes to allow for the bolts to fit. Some aftermarket manifolds have this already machined into the manifold. Should not touch the heads.

Now is there a big power difference between the two? Eh thats debatable but would depend on the manifold and cam used

So 85 and 86 are identical to the original SBC bolt pattern heads with later models only having this slight angle change being the only difference?