Rag joint elimination???

[MPETE]

I am hoping to replace my rag joint with some sort of U-joint setup. Whether it be flaming river or CCP or what have you.
I thought I was ready to buy parts, but I am confused and looking for some answers.
Everything I read says the replacement joint needs to be 3/4" 30 spline on the steering box end and a 1"DD on the shaft end.
OK, sounds simple enough,
Then I look at Steering box info and depending on where you read it says the steering box input shaft is a 26 spline.
What gives?
Is it because of the flat section on the input shaft and the u-joint is splined all the way around and not "keyed" like the input shaft? Or is there something I am just not getting?
Am I just overthinking this? EVERYONE seems to be unanimous on the the fact that the 3/4" 30 spline is the part to use, I just don't seem to understand how a 30 spline opening fits on a 26 spline shaft.

[2kwik4u]

I'm not of much help on what sizes are which, or which is correct even.

I did however stumble across an unopened jeep style steering shaft in a box this past weekend. Shoot me a PM and I'll send it your way this week. You can test fit, measure, whatever you need to do with it. If it fits it's yours, if not well, then it's still yours.