Now another issue. So i purchased a 260 3 speed driveshaft yoke(63-64). Matches identical to the other yoke i replaced ( bearing cap size, outside snap rings, overall length, etc) with the exception that it is now the correct 25 spline instead of the 28 spline. I test fitted it into the tranny tail shaft and it is indeed a match. I installed it on the driveshaft in place of the 28 spline yoke(that now appears to have been from a later 3.03 3 speed, 65 mustang?). But, when i go to install the driveshaft, the yoke will not go any further into the tranny and i need about another 1/2 inch or slightly more to get the u joint to go into the rear axle yoke. I measured the drive shaft and it measures what my restoration book states as correct for 260/289 3 speed b4 DEC. 1964 as 50 25/32 ". Now, the car is raised up on dollies in the rear so i didn't jack the rear up any more. If i could install it with the car raised up, would it bottom out with suspension travel? I wouldn't want anything binding. Any ideas what could be keeping the yoke from going any further into the tranny? When pushed all the way in, there is about 2" from the tail shaft seal to the base of the yoke. Does anyone know whats the correct distance for this? Thanks for any feedback. I guess if i had to i could get the driveshaft shortened by 1/2 or 3/4"? I,m sure that would be a good $100 for 1/2 "!