Problems starting

I recently put an AOD unit out of an 89 Grand Marquis into my 68 coup that had a C4 in it. Since I put it in, it just doesn't work right. Just tonight, I tried starting it and the starter wouldn't fully engage the flywheel (it sounded as though it was slipping and grinding :damnit: ). I used the same starter as I did on the C4 and the flywheel is the same, so the distance hasn't changed as far as engagement.
The enigne is an '87 351W out of a crown vic and the tranny from an 89 Grand MArquis. Any ideas? New starter?

Ttt

Thanks for all your help!!! The starter was loose.