I would always run the closed chamber Edelbrocks over the open unless you NEED the open chamber heads (like with stock 340 pistons).
Aluminum heads dissipate heat much better than iron, that is why you can run more compression with aluminum heads and not run into detonation. Typically, you can get away with premium pump gas and 10.7:1 (even higher compression depending on cam selection).
Also to note, stroker motors eat up cam duration...meaning, you can run a larger cam and it will "act" like a smaller cam...if that makes sense (max power will be at a lower RPM than advertised).
