Reaming out axle ends to fit larger king pins, weakens the axle ends. As long as both trucks are about the same gross weight, if the air brake king pins are larger, one can bush up the smaller king pins with steel sleeves, or custom fabricated bushings, which are relatively inexpensive. That is assuming all the other parts play well together.
Ed
'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.
