Got 4 flats of tools tonite. This Snap-on S9580 was in one of them. Couldn't find it on Murch's site. Doesn't mean its not there just that I couldn't find it. What is it? The 040 offset screwdriver of 1959 just crept into the picture.

universal joint assembly tool

as you said its on the site, just hard to find

 Found it. 1936-1953 Chevy-Pontiac. Not sure I could find it again but thanks to Skips I D it showed up.