I dont think GM is doing too bad with there 2 valve heads.
Stock corvette heads flowing 360 -380 cfm

Edelbrock is comming out w/newer replacement heads that will bolt on LS1, LS2 & LS3 blocks & will flow over 400 CFM

All pro LS heads been flowing over 400 + cfm 2 valve head.

4,5,& 6 head bolt pattern.

Look @ the new Corvette run a 10.7 all stock
http://www.youtube.com/watch?v=woOqqfGtqHo&feature=player_embedded


MBHD

12 port SDS EFI