That sounds like a fun combination. Someone ordered that combo in purpose I'm sure. Yes all sorts of crazy combinations that don't fit the written information. Never mind say never with old Mopars.
It was a great running car. I wound up running in Z/SA. Just as a FYI. 3.91 was the lowest gear set offered as a factory ratio for the 7 1/4 rear. However Direct connection did offer 4.11, 4.56, 4.88, 5.13 (I have a 5.13 set) I have heard of a 5.38, but have never seen one, or a even listing.
