I don't know who needs this, but. . .
when replacing your control arm bushings with the Energy Suspension kit 3.3140G or 3.3140R (for 4 link Vegas), it says to retain your upper control arm bushing sleeves. If you find yourself needing to replace one (because you cut it out like me) here is the info.
stock rear upper control arm bushing GM #3978060 which is discontinued.
Moog has a part number for it of BR139, but it's discontinued.
Interestingly the Moog pn BR139 crosses to a Ford Pinto bushing #D1FZ-3069A
Using the Moog chart below, (that I stole from pirate 4x4) it crosses over to several part numbers. None were available.
Ultimately, I got one from Rare Parts Inc (Part #15139) ordered through Auto Zone because Amazon didn't have it.
https://shop.rareparts.com/search?keywords=15139
I put all the discontinued part numbers and information in to help someone who has the discontinued part numbers if they use the search function. Good luck!!
https://www.pirate4x4.com/tech/billavis ... ence_2.pdf