1970 LS5/LS6 Driveshaft question
 

Did these use the "3r" type u-joints front and rear with OE plastic injection retained caps, or did these use a 1330 with external clips?

454's used plastic injection to hold the caps. 396 shafts used external rings.

What confuses me is that the Yoke on the 12-bolt seems to be set up for external tabs and not internal C-clips like you would find on a 3R type joint with the factory injected plastic.

Did they have a conversion U-joint or something at the rear, or did the rear joint still have the cups with grooves for internal C-clips / plastic where it mates with the yoke? What is the diameter of the u-joint caps used with the 9210 rear yoke?