the six needs special attention. I do not know what that attention is..but a cam can make or break what I don't know about.
I wanted to make a hot rod out of a 200ci 6 cyl ford in a zephyr...mechanic advice: do not even bother.
there is indeed an assymetry built in... an old pro should really know.
if you note the intake, see all that distance change from middle cyls to outer, that is only part of it. If you symmetry eveything to perfect, the six will shutter...and I am certain the cam has alot to do with it. changing ratios on the same cam timing might reveal it..
the 300 being a big one...someone must have tried hot rodding it. the 200 I had was impossible.