[tubman]

If it were me, I'd try the Warford backwards (if it's in decent shape). I think you said the splines are the same on both ends. Do you happen to know the ratio? I believe overdrives need to be stronger than undedrives because of the way the gear multiplication works, but it should be plenty strong in any case. Also, If you were to put a real heavy load on it, you would probably want it in dIrect drive, which should pose no problem.