what wrenchbender sez is no, there's no better gears available for the stock 3/4T rear, but an overdrive trans will give the same effect ... or find some other rear end that'll fit, with better gears
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics