Ok, this is where you are going to make power, modding the cyl head, that & a decent camshaft.

Larger valves, lumps pocket/bowl porting minimum. It is going to cost though. It is not cheap period.
If you are going w/307 flat top pistons (w/no chamfer on the top sides) you need a better cam to complement all the others items you are going or intend to add.

It all depends on what you are looking to get out of it.


MBHD


12 port SDS EFI