ujoint tight Q

63 dart 360 high banked dirt track stock car. I had the shaft shortened (& balanced) to fit with an inch of end play. when I picked it up the rear ujoint was too stiff in both planes along with the front yoke being stiff (in one plane). I took it back & they corrected it some but it still seems too tight (to me), not smooth like the front yoke is in the one direction. do you think I will have a problem. max RPM will be 6K. thank you for your time. RR