the 64-65 have the Ball and trunion the 66 is a slip yoke they have a 3.09 first gear which will fry the tires easy the later 4 speed have a 2.66 first really weak take off compared to the 3.09.
1964 thru midyear 1966 A-body 3.09:1 - 1.92:1 - 1.40:1 - 1:1
67 and up 2.66:1 - 1.91:1 - 1.39:1 - 1:1
As long as you have the ball and trunion drive shaft just run it those are strong transmisson PERIOD
