While you are searching, might want to think about anticipated use, freeway, rural roads, short or long trips, etc. 6.17 with a direct trans. Will take a while to get there, be a road block on freeway, OD trans. Would help some, otherwise might want to consider higher ratio rear gears.

'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.