[**grumpy**]

My solution was to swap a 72 C10 3.08 rearend in my old 64 which had a granny 4spd.

The difference it made was so dramatic.

I could treat the granny 4spd as a normal 4spd. And it would run 75 down highway all day and not scream.

I actually have 2 more 72 rearends with 3.08s, one is a posi.
just to have for future projects.
I buy every one I run across.