My '63 has a TCI 4 link and I just converted from a 350 turbo to 1971 4 speed Muncie M20. I now have about 3/8" driveshaft clearance at the yoke/trans, and everyone recommends 3/4" to 1". I removed the shocks and moved the rear end up and down and saw very little movement of the yoke in or out of the trans, ao I thought I'd just try it. I broke the motor in and drove the car easy for 20 or 30 miles, but the first time I jumped on it in 2nd and broke the tires loose, it wheel hopped. I'm thinking I may be bottoming the yoke into the trans output and the bind is causing the wheel hop. I plan to have the shaft shortened 1/2". Do you think that might be the issue?