Another alternative is the 516 head. They were a closed chamber design but really should have a mild port job as well as machining for bigger valves for the most bang for the buck.
If you are doing a pump gas engine, you might want to deck the block and run a shorter(lighter) piston. Alot of guys do this and run BBC pistons. The stock dimension Mopar stuff is really heavy. Also, those big blocks are sensitive to detonation so by decking the block you will have better quench which will help on that end. Good luck, and happy tire-frying to you!!
