Regarding the Teflon seal…suggest you look at this old Glen Jarboe thread. Also look at the link to photos within the thread. When I attempted to put that Teflon seal in my 3.8 with the engine on a stand, I had the same gross distortion problem Glen Jarboe describes. I solved it by carefully reducing the outer diameter of the seal per Glen’s recommendation. But that could be a real chore with the engine in the chassis. Mine doesn’t leak, but there’s zero doubt it would have if not resized. I’d use the standard lip seal.