Too Much or Not Enough.

[1969 Stang]

I bought all the typical mods for my motor and it still does not seam to have the power i want.

Holley 4160
Ported performer dual plane
Windsor sr. heads.
hooker super comp headers.
free flowing exhaust.
Comp cams roller rockers 1.6

only thing stock is cam.

so thinking im running lean or rich.
haved tried many jets from 65 to 68's and cant seem to find any differance. plugs look tan and seem so make no change.
also tried plug gap with no differance.

what is restricing my power here? what else should i try.
only thing left to upgrade is cam.

motor builds rpm pretty good but just does not seem to have it.
c4 trans with 3.55's 2,800 lbs 66 coupe.