Rag Joint to U-Joint

[biohazardbill]

There is a PS box on my 65, not factory, not sure what it is off of. The rag joint is broken. I will be putting in a different steering column soon. I thought about having the new column machined to fit a u-joint and figured I could replace the rag jount itself with a u joint there.

Doing some measuring it seems that the PS box has a 13/16 shaft so looking at some u-joints I see there are some 13/16 36 spline joints. Is that a common shaft/spline for a chevy PS box?

Also at the end of the shaft it appears there is a nipple that sticks out about a 1/2" id say. Would that interfere with the joint or should I grind that off?

Thanks in advance for any insight you provide.