Just went through a bunch of broadcast sheets for this driveshaft thread: '71 Barracuda driveshaft

The 636 is used on 383 auto & 4-spd and 440/426 auto.
The 769 is used on 340 auto & 4-spd and AAR. one "big" one "small" u-joint

They are both listed as "big" u-joint, but I am unsure of any differences.
I believe the 636 is 3.25" end to end and the 769 has a taper in the tube length.

Last edited by 6bblgt; 09/21/10 07:43 PM.