3/4 ton drive shaft to 1/2 ton rear???

[67Blacksheep]

Guys-
Forgive me, as I know I posted a similiar question a few weeks ago, I can't seem to find it though!!
I just got my 1/2 rear in place. The u-joints from my 3/4 ton shaft are big, the 1/2 yoke on the rear is small. My question is...what u-joint combination do I get??? Or...can the yoke be swapped from the Eaton onto the new 1/2 ton??? Will the caps change over?? Any help would be great, as I have been fighting this swap for the better part of last week.

Thanks-
Sheep

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67 Chevy C20 LB Stepside,
350 4-bolt with goodies.