[ATTACH=CONFIG]530223[/ATTACH]
Cmi headers come drilled with both bolt patterns

not all, that was the reason for my post, mine must be the sweepers,

Great to know, I will drill them for both!!

Another question on the same platforms: Intake Manifolds. Will they swap from a 502 MPI to a 525 EFI? Could you take a 502 MPI and run the intake manifold set-up from a 525 EFI manifold set-up on it?

Yes, the 525 is a 502 based engine

Excellent, we should have a very cool project underway shortly! Thanks!