383 power upgrade help

Speaking from direct experience - If the pistons are .100 in the hole angle milling a set of Stealth heads from the big side of combustion chamber .040 will bring the compression to 9.3-9.5:1 with a .040-.051 head gasket. You could do better with a little more work but 9.something CR will make 450hp no problem.

If you add up the cost of doing guides, big valves, seals, hardened seats, porting consumables, decking, magnaflux + pressure testing you will not be too far from the cost of a cheap set of aluminum heads. A stage two ported set of 906/452/346 won't even get close to the Stealth heads out of the box without sacrificing reliability.

As mentioned the E Street heads are also a good option if you want a less traditional appearance.