The trans is probably a non-synchro, 4 speed, which will probably hold up to the V8 OK, if not hot-rodded. A more modern rear axle w/ highway ratios would be helpful down the road, at which time one could use a modern 420 or 465 trans, need to modify or change bellhousing-see another thread here about that. Not sure about the price, though.

'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.