qustion on what universal steering joint for mustang to to gm column

need to know what type of joint used from mustang 2 rack to a d shaft,then i imagine a 3/4 dd to 3/4 dd on teh bottom of teh column? forgive my ignorance,mustang 2 is a lil newer than my last project and im drawing a blank

 

my mustang rack looks like its 5/8?? thats a bit odd isnt it?

 

Power steering rack is 3/4" x 36 splines
Manual rack is 9/16" x 26 splines.

 

mine measures 5/8

hard to count the splines tho its in a tight spot on the truck. but for sure its 5/8 i put a 9/16 socket and it looks that size put its deff more than 26 splines. i got to 25 and couldnt reach or turn to see more but felt them

 

measured and looked again, i think its a chevy rack on the mustang 2 kit,its 5/8 and 36 spline. chevy has that in the books so i think thats it. it does have a flat spot on it.im ussuming for the set screw