No one answer, a lot depends on the terrain. Was running a 3.54:1 (dana) in my '60 w/ 235, was too high geared to pull hills good in direct. Now running 3.73 pulls hills much better.
I've got a K2000 (old body GM400), 5.7 / 4.10 10.5 full floater, NVG4500 , pulls storng. Wouldn't want any higher gears.
