Not sure which case you are chasing, but a np241 should do the trick. Somewhere between 88-92 is what you're looking for, obviously passenger side drop. Somewhat hard to find. Not only will it allow for hookup to your auto trans, but also has vss, which is important. The adapter (if the 241 is behind a 700r4) should be the same at the 80e I think, but don't take that to the bank. Worse case, sell off the 80 and get a 60, I know they bolt up for sure.
I don't know why everyone is scared of DBW. I prefer it now that I've tried it
See this thread
http://ls1tech.com/forums/conversion...silverado.html
It would actually be easier to keep the dbw. If you go cable, you need to switch throttle bodies, change ecm, run cables, etc. With dbw, all you need to do is find a pedal assembly with the wire and matching tac module. It just plugs in and goes. There is no lag, there is no performance loss at all. Plus, if you keep vss, you get cruise control for free.