351w heads

You can put GT40s on there and get a pretty nice bump in compression compared to the 351 heads (depending on the year of THOSE heads) but you'll have to drill out the head bolt holes to 1/2 to fit on the 351 block. The '69-70 C90E heads are nice for stock 351W heads, and have a lot of potential with porting (i'll be low 12s with mine as soon as it'll hook). Before Ford starting putting the iron 40s and 40Ps on production cars, the C9s were the heads to have as far as stock heads go. Porting and polishing aside, you'll be better off with GT40/40Ps than the C9s...i'd be running them myself if my heads weren't ported as well as they are.

My 351 heads were great. Flowed well, and worked GREAT with a RPM intake.