Early Mustang and Corvette pitman arms interchangeable?

I'm going to use a manual box that I was told is GM (Corvette or Pontiac), quick ratio (3-3/4 turns) the sector shaft is about 1" (the 605 is about 1-1/8").

I need an pitman arm about a 7" with a 1" sector shaft hole. the one on it is only 5-1/2" form center to center, the draglink hole on the p***enger side is 7" from kingpin center to tie rod hole center.

Does anybody know if a 67 Mustang manual box (1" sector shaft) has the same abount of splines as the 1" GM sector shafts?

 

Your chances here are very good if they're the same diameter--I have found a great deal of interchangeability form 1932 up into the eighties on non-power boxes, even between corporations. Everyone must have been buying the same spline broach from the same supplier in Detroit since the dawn of time.