I have a mercury 1994 Grand Marquis that has a ford 4.6L Cast iron V8 Engine which to my knowledge is the same block that is used in the Mustang GT.
My Drivers side cylinder head needs to be replaced and I cant really find any heads that are said to fit my car and the machine shop that my block is currently at wants around 400 for a used head so I found a pair of mustang GT cylinder heads online with casting number F5ZE and year 96-98.

My cylinder heads have a casting number of F5AE. If I get the mustang head I plan on replacing both heads as to not have an potentially unbalanced engine.
my Question is will the heads fit my block? my primary worry is that the head gasket and bolt pattern may be different. Whats the difference between the F5AE and F5ZE casting numbers?

Heres the link to the mustang heads

 

I don't have much to offer since I don't know what casting head numbers mean. I can only suggest to check with a local car salvage yard. They used to make cross reference manuals for car parts to tell what part will fit what car. I assume they still publish them. Just a thought.

 

They are the same heads. The 3rd number indicates the car line. The "A" indicates Ford, & the "Z" indicates a Mustang.

Goggle "Ford Casting Numbers, & you will find all the info on Ford Casting numbers.

 

depends on the amount of valves in the heads since some of the higher performance ones are 3 valves not 2