I've always liked how Ford did it. A lot of their four barrel engines were different right down to the pistons. BIG ports, BIG valves, more compression. What I never got was why they used RETARDED camshaft timing. "I GUESS" they were fighting emissions. Had they just ground advance in their cams through the muscle car era, they'd given Chrysler a run for the money. I've said as long as I can remember the Cleveland couldda been a Hemi killer.....and it's true. The small block that couldda beat up a Hemi.
