I've run the neoprene seal on the front of my 8BA with good results. There are several variations out there - Hot Rod and Custom Supply in FL has one with an aluminum housing that doesn't need silicone around the body. Other places are selling a standard grease seal that requires silicone caulk around it to prevent seepage.

Rear? There are no non-rope replacements. I've heard about using the Buick V6? rope seal, but have no personal experience. Go over to msn groups and check out the techno page - rumbleseat has the best info on seals that I've seen.

edit: here's the link but I don't see what i'm looking for - still good stuff to keep you busy...
http://www.btc-bci.com/~billben/flathead.htm

this link will take you to a large pdf file that contains rumbleseat's musings - some of the best darn flathead info available from a regular guy that lives it. In the middle is his engine info including the rear main seal stuff. Worth every minute it takes to download. I've printed it off for my own reference.

http://groups.msn.com/FordFlathead19...seatstips.msnw