Dan the Gear Man Tech® Note 1:
QU20101 yoke is made to take universal joints made to special Spicer 1330F series external snap ring universal joint specifications. The u-joint cup diameter for the driveshaft yoke should be 1-1/16". The u-joint cup diameter for the pinion yoke should be 1-1/8" and the overall width of the universal joint should be 3-5/8". See TK40723 and QU40776 External Snap Ring Universal Joints
Dan the Gear Man Tech® Note 2:
This 31 spline yoke has a length through the hole of 1-41/64" so it will fit late 10.25" rear axles, but it will not fit early (1985-1992) 10.25" short pinion Ford axles. See QU20029 for a short spline Pinion Yoke.
Dan the Gear Man Tech® Note 3:
When replacing an old pinion yoke, always replace the pinion seal, pinion nut, and crush sleeve. Replace the u-joint strap kit and outer pinion slinger as needed.
Order these matching parts separately:
QU40841 U-joint Strap and Bolt Kit
QU20050 Pinion Seal
QU20002 Pinion Nut
QU20003 Outer Pinion Slinger
QU20000 Crush Sleeve