52 GMC half ton 350 high output crate motor with claimed 340 horse backed by a built 700r4 with a one wheel peel open drive rear maybe 3.10. I want to put a posi in so while its open, change gears, we do lots of long hauls and quite often pull our old camper maybe 3500*. Right now running 60mph around 2000 2200 rpm what gears would be ideal for snappy around town and hyway hauling. Snappy, never thought I'd ever say that, must be getting old. Thanks.......Snappy,, kinda growing on me.