After a little bit of searching I figured out that the U-joint in my Beavertail 13hp LT is a Spicer 5-170X. Napa has a cross reference to PUJ338 part number which is acctually a Spicer joint in a Napa box.

I picked this up for $13 instead of the $93 beavertail wants for the OE replacement on their website.

Since I wasn't able to locate this info, I figured I would post it up, maybe someone else can use it.

Good on you!