Rooster Comb and park switch

So I have a 904 out of a 68 dart that I rebuilt to install in my 70 dart. I have left to install the valve body which I did change out the rooster comb with a 70's something rooster comb to match up with the 3 prong neutral/park switch. The issue I am having is when I put my valve body on and rotate the shift shaft to the park it does not want to go all the way in to park and the ground tab on the rooster comb does not rotate far enough to ground the park switch. What appears to be happening is that the stop on the comb is hitting the stop on the valve body before the detent ball falls in to place. My question is, is the 68 valve body different then the 70 and later or is the stop on the 70 and later comb different then the 68 comb and if that is the case can i grind down the stop on the comb to allow it to rotate where it needs to for the detent ball to fall in to place on the comb and allow it to rotate enough to ground the switch?