Identify Ford Heads Type

[mi69camaro]

I pick up some heads that were on a 302 ford motor and i am trying to identify them. The casting number is #D5AE. It also says 351. We are trying to identify if these are 351 heads or not. if you know how to identify these heads please let me know ASAP.

Craig

[wilfie27]

Sorry so late

Those heads can be either 302 or 351, the only difference is the size of the head bolt holes, 302's are 7/16" and 351's are 1/2".

[MagicRat]

Originally Posted by wilfie27

Sorry so late

Those heads can be either 302 or 351, the only difference is the size of the head bolt holes, 302's are 7/16" and 351's are 1/2".

Not quite.
The part number "D5" means 1975 model year

In 1977, Ford used the same castings for the 302 and 351, so your comment applies for that year and some later years.

However, before 1977, 351W heads for any given year had slightly larger combustion chambers than the standard 302, with slightly larger valves, an extra intake manifold bolt and L-shaped water jacket outlets on the intake manifold side.

Are you sure you have a 302 there, and not a 351? They look very similar.

It is possible to bolt on 351 heads to a 302, (Ford used to offer a kit to do so) but they reduce the 302 compression ratio about 1 full point unless they are shaved.