I know the GT40-P head number is F77E-BA but what is the F67E-BA?
My local recycle yard has the F67E-BA heads from both a 1997 Explorer and a 1997 Mountaineer. Is there a difference? Could it just be AIR in head or AIR in exhaust manifold?
F6 = '96
F7 = '97
As far as I know anyhow. I think that would be the difference between the GT40's and GT40P's in this case. They switched to the Ps somewhere in the 97 year, so it's still possible for a '97 to have the F6 heads.
Maybe
If you can run down there, could verify by the 3 vs 4 bar casting marks.
If the 93 Cobra/ 95 Lightening F3 head has smog bumps in the exhaust port and the F67E head does not, that might explain the different numbers. Somewhere in there Ford went to air injection in the exhaust manifold. Then, the later 1997 revised plug angle GT40 head ends up as the "P' head with an F77E number. If I'm correct,wouldn't the F67 head be a better choice if you're not concerned about being smog legal?
Don't beat me if I'm wrong about the smog bumps, I've never seen an F3 head in person.