261 engine, or GMC 302, Chev 292-both need to move radiator(larger) to front of cowl support. OD trans., no options for rear axle-substitute modern dually rear, depends on bolt pattern-6, and 10 lug easy- D70, 80, GM 14 bolt-8 lug only. Disc brakes and shocks(if not there) on front. Tighten-up all steering apparatus, substitute Saginaw power steering/linkage. 22.5 tires and wheels.

All these ideas in this forum, recently.

'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.