12 G is with manifold valves springs rockers covers. They are the best thing out there as far as I know.

The hilarious part to me is I was just looking at a hammer headed small block ford at engine systems. 500+cfm small block head, copied after a boss 9 head. 400ci 1100 hp at 10,000 rpm NA. Those heads are cheaper than the predators lol...they also use a wedge manifold so there are dozens of shelf manifolds . Single 4, 2 x 4, blower , turbo, efi shelf manifolds...those heads are also offered as direct bolt on for the chev LS platform...alas, no mopes

I so wish mopar had these options. I still love a blown hemi though...and that still is the top dog in all drag racing period end of story lol