c7ae-a and c8ae-h heads

[olman]

I have a set of c7ae-a heads with 16 hole bolt pattern and an extra hole on the end ex. ports below the factory holes.  Also have seen 16 hole  c8ae-h heads the same. What were these lower holes used for ?

[thatdarncat]

I have a set of c7ae-a heads with 16 hole bolt pattern and an extra hole on the end ex. ports above the factory holes.  Also have seen 16 hole  c8ae-h heads the same. What were these upper holes used for ?

The Fe heads used on cars with shock towers ( Mustangs/Cougars/Fairlane/Comet ) had 14 exhaust bolt holes, and that would include the C7AE-A & C8AE-H heads - the top row end ones were slightly lower than the center two, and lower than the normal 8 exhaust bolt pattern position. Also stock the two lower center holes were not drilled, which is why they only had 14 holes. It's possible to drill & tap the missing lower ones to add them, the material is there, likewise you can add the cross holes on any of the '66 & later heads. If the extra end holes are a problem making headers seal a lot of people just plug the extra hole.

So more than likely someone drilled the extra holes to accommodate both patterns and that's why you have the extra end ones. Pretty common do, especially if someone was trying to make some headers or exhaust manifolds fit.

[olman]

Right, I understand that, but my heads have 18 holes on each head, 1 hole just below the top hole on the end ports............ Oh wait I see what you are saying now, so you did answer my question Thanks!