As an FYI, I took a little look-see to compare GM's DOHC vs. Ford's DOHC (strictly power output, that is). I'm comparing only equivalence (not comparing a 4.6 to a 5.8). I cheated, though, and simply wiki'd it:
Naturally Aspirated:
GM 4.6 - 320hp/315tq (05-10 STS)
Ford 4.6 - 320hp/317tq (99/01 Cobra)
or 310hp/335tq ('04 Mach1 if you care more about torque)
Supercharged:
GM 4.4 - 469hp/439tq ('06-'09 STS-V)
Ford 4.6 - "390hp/390tq" (03/04 Cobra; parens because they are underrated).
What's my point? GM is (was?) certainly capable of competing head-to-head
