Too much torque

SirDan said
I've heard most 4 speed trans are 727 style yolk which you can likely get a bigger u joint yolk. Some did have 904 style yolks though. But you might be able to get a bigger U joint yolk for that out of a truck or van.

Looking online, 904 is a 25/26 spline count and 727 is 29/30 spline count.

Hope this helps a bit, someone here probably can tell you a bit more about what to get.

I think what I am going to do is go with a 2.5 ton old military surplus ujoint. You're right when you say the yolk is almost the same. When guys took a /6 and dropped a v8 they used the same yolk and ujoint. Why mine broke is beyond me lol