69Mach1 M code 20 Report post Posted November 13, 2021 I am swapping out an FMX with a 4-speed toploader. Can anyone tell me the proper amount of engagement between the output shaft splines and the yoke splines? I need to measure the driveshaft length to have it cut and balanced. The toploader did not come with a yoke so I'm starting from scratch. Quote Share this post Link to post Share on other sites
Vicfreg 790 Report post Posted November 13, 2021 I push the yoke all the way in, and make a mark on the yoke at the rear of the transmission. Then, pull it out 1" and mark the yoke again for reference. Ask the person who is going to make your driveshaft how they want it to be measured. Typically, it is from centerline to centerline of the u-joints. A CRITICAL step is to make sure the weight of the car is on the rear suspension when you do the measuring. 4 det0326, GypsyR, stangs-R-me and 1 other reacted to this Quote Share this post Link to post Share on other sites
GypsyR 34 Report post Posted November 16, 2021 I also like to see one inch of "play" as a rule of thumb. Measured when the vehicle is resting normally on the ground. Or better, on a four post lift. Quote Share this post Link to post Share on other sites
