Its a factory LS1 driveshaft. When I tried to put the driveshaft in, the tangs on the 9" yoke (see yoke ) would keep the ujoint from sitting all the way down. Basically the factory ujoint was too wide (3.75"). I got a combo u joint (napa 240-0447), but the caps are too big for the yoke. It has the right width, (~3.65"), but the caps are 1.19" vs 1.125" for the "1310".

I thought about using the GM caps on the combo ujoint ends (that are the right yoke size), but they do not seal well when put on the combo end. Any Ideas
(aside from pulling the yoke... )?