Read in here about Grigg's conversion putting modern disc brake spindles on your front axle. A GM 14 bolt axle will provide a modern axle with higher ratios. Ratio depends on engine choice. A 292 Chevy would provide adequate power, that would still use your existing 5 speed and hydraulics. Need to move radiator fwd in core support. Best to find out what 5 speed you have with pictures and descriptions here. Could be Clark-Ci top cover, 3 shift rails; NP-540 series, Al top cover, 4 shift rails-

Of course, if really want a V-8, then other engine compartment changes required. Could still use Clark or NP trans.

16, 17, 19.5 or 22.5 tires and wheels are some choices, depending on axle selection.

Others will surely comment.

Ed

Last edited by EdPruss; 05/05/2018 12:10 PM.
'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.