this rear axle stuff is confusing, but I have to go posi

[Mike C]

There are some differences with the yokes. Most 12 bolts will have a 1310 u-joint size, but big block 1/2 ton trucks will have 1330.

The 1330 is same diameter cap as the 1310 with a wider cross. The 1350 has the wider cross of the 1330 as well as a larger cap diameter. Most likely the donor truck has 1350 joints already I would think. But you can measure cap diameter and cross length and Google will let you cross reference those things.

So yes, you can use the 2500 driveshaft after it has been shortened and balanced. I am assuming it is a one piece shaft. I know you can buy 1310-1330 conversion joints but I’m not sure if you can get a 1310-1350 conversion joint. Meaning you may have to buy the yoke for the rear or a different end for the 2500 driveshaft.