289 block, 302 heads

[Hugh Pratt]

Hello, I have a 65 fairlane, the block is a 289 C6AE-6015-C. In trying to find out the head codes I discovered they are 302 heads. Is this normal and if so, what does this make my engine.

[MagicRat]

Do you know if your engine is original? C6 is a code for 1966.
There is a difference between years for 302 heads. Generally, the early 302 heads (1968 and earlier) are the same as 289 heads.
In theory, 302 heads will give you a slightly lower compression ratio, however, Ford did not seem to care.
In 1968, Ford made 289 and 302 engines, both using the same cyl heads, with 61.7 to 64.7 cc chambers.

302 heads made after 1968 will definitely give you a lower compression ratio than what your 289 had originally.

Therefore, depending on the year your heads were made, they either are virtually identical to original, or will result in lower compression.

[Hugh Pratt]

Thanks magic rat for the info. The 289 is a 1966. Even as it is, with the performer intake, the headers, it obviously has a cam as well with a good carb (4brl). The rockers have a large hex nut with a small allen screw in the center, I don't think ford would have made this at the factory normally, so I really wonder what else is inside, it REALLY revs. So well in fact, i believe I will re-gasket most of the engine and run as is, it is really clean under the covers.