I recently purchased a 97 F150 4x4 with a 4.6. I purchased heads from a reputable cylinder head re-manufacturer and received them today. However, I noticed the casting numbers are not the same. The heads that I removed from my motor were RF-F65E-6090-D20A. The heads I received are RF-F75E-6090-C20A.
I am wondering if they are ok to use. I asked the guys who remaned these heads but I was too late on my response due to the time difference from coast to coast. I inspected them thoroughly and found small differences; but they weren't major.
I'm hoping I can use these since I am leaving town for two months and need to get this truck together before I leave. Any help or insight is greatly appreciated!! Thanks!

 

As long as you have a Windsor (VIN 6) engine, those are the correct heads. There may be intake gasket differences.

 

As long as you are installing non PI heads and using the original non PI intake they are fine. Any small casting change no matter how small will change the casting number. Even Romeo cyl heads will work on a Windsor block however the Windsor cam covers will not be compatable with Romeo heads and visa versa.