Driveshaft help

Just put a yoke in it and measure the distance from the U-joint centerline to the bellhousing face on the two transmissions. The difference will give you a pretty good idea how much longer the new shaft needs to be. Best way to do it would be to measure it with everything installed, U-joint centerline to U-joint centerline, with the weight both on and off the suspension in case there is any unused fudge factor in the existing setup. Want to get all the yoke spline used you can without bottoming the yoke when the suspension unloads.