Will a motor from a 96 500e bolt into an 04 500f frame?  The frames look the same but were there any small changes that make parts incompatible between the 2? Thanks

It will fit exactly the same. As example, I have a 2006 motor in a 1993 frame.

thanks for the quick reply...thats pretty much what i figured, just wanted to verify

Mechanical speedo vs electronic. I think that's all.

If it is a 2004, then it already has electronic tach and the wiring. You'll need to plug the mechanical tach hole with a short bolt and washer.