340x vs. Edelbrock aluminum heads.
You can port the X heads father than OOTB Edel. heads, but the intended useage may very well say, save your money. A mild bowl porting on set in a full weight A body can go 12's.
A few fellas, a few years back were coupling up the MP shortblock (10-1 version w the 292 cam) and a Edel. RPM intake and heads w/750 cfm carb, headers and 391/410's and running low 12's.
Bowl ported X heads and new valves Vs. OOTB Edel. heads are about a equal price and payoff. If the engine is a lower comprewsion engine, the Edel. heads will lose power due to being Aluminum and there acco. heat lose with the aluminum.
I have a set of Edel.'s and there good.