Stock 1979 360 with Speedmaster head question

Fel-Pro 1008 for head gasket is the most common go to. But, how far in the hole are you pistons? I'm assuming they are 0.030 or more, so no head gasket will get you into good quench territory. You'll need to deck the block and/or replace the pistons to really take advantage of the closed chambers.

There is more to just putting them on, a push rod check and rocker geometry/wipe checks should be in order plus degree whatever cam is in it.