Originally posted by DennyW
I just thought I would throw this in, general info, that's all.

Big block oval port cast iron heads were made in two different configurations. The large oval port heads found on many passenger vehicles and trucks and the small oval port heads (which are also sometimes called peanut ports or round ports or truck ports) found on many big block 454 truck engines made after '76. Each of the oval port head sizes used a matching intake manifold. If you are building a motor for pulling or towing on the street, the small oval port heads will make their power at low and mid range rpms, but run out of breath at rpms over 4500. If you are building a strong street performer or a bracket racer, the large oval port heads are the ticket up to about 6500 rpm if you do some bowl porting and add the 2.19"/1.88" valves. Some of the better performing cast iron large oval port castings are the open chamber designs like the "781" or "049" casting. You can get an aluminum version of the large oval port, open chamber head under casting number "391" from GM/Performance Parts.
He already has a set of 781's.