My 80 had a transplated 22r with a 5 speed 4.30 gearing, double roller chain, Downey header, 20r hilux head, etc, etc, rolling on 35's. on flat level ground with a tail wind I could get 75mph in 4th shift to 5th and it wouldn't hold the speed. 5th gear is a waste of time unless you are going downhill.
