Still need pics of 66 shifter arms? I could take a few shots this weekend if you do.
Many years ago, I swapped in a later 3spd Muncie(?) trans into the 63 I had then. As I remember, the lower end of the later arms were grafted to the upper ends of the early arms and then with some tweaking to fit better, it worked, but not well.
It seems there was some flex or poor angles that gave it a less than positive feel. A local trans shop did the work for me, and I never tried to improve on it before selling the truck.
