I'd assume the u-joints are probably different,GM probably had two sizes they used depending on the transmission & rear axle,so you'd need to measure the u-joint cups and cross dimensions to get the right yoke.
FWIW 99% of the rear end yokes I've seen installed when a pinion seal gets replaced at local garages, get tightened with an air impact gun...they guess at the amount of "Ugga-Googa's" it needs and rarely does a rear axle come back with issues..
Yeah,its not the "right" way,but seems to pan out in most cases..
It's not easy trying to tighten the pinion nut by hand using a pipe wrench to hold the yoke from turning while applying enough torque with a breaker bar & socket lying under the truck--even on a lift its risky,the truck might try to move off the lift arms while your tightening the pinion nut..
