For those interested, I put all the details of the A/C system rebuild in my overall truck build thread - the A/C stuff starts around post #654, on page 66 ->
https://www.gmt400.com/threads/talk-me-into-or-out-of-it.60810/page-66
A couple notes about all the stuff I ordered:
The particular Orion gauge set I bought was the wrong kit, sorta. It only came with the piercing can tap for the old style cans. The new R134a self-sealing cans require a blunt tip can tap, so I had to order that separately. Orion does sell a kit that includes both.
The GPD "compressor kit w/condenser" - condenser came with the black orifice tube already installed. So, the one they included with the kit, was redundant. I switched to the yellow orifice at L31's advice so didn't need either one, and they don't cost hardly anything, so it's no big deal.
The kit also came with a bag of seals, none of which I needed.* Every component came with its own o-rings already, so I've got a bunch spare now. (previously thought I needed the compressor sealing washers but when breaking down the boxes I found those too, under the packing.)
The compressor came pre-filled with 7oz of oil, and in my case, system capacity was 8oz, so I only added a small amount from the extra bottle I bought.
The one big disappointment was the GPD suction/discharge line spec'd for the 1-year-newer model of my truck - 1994 C3500 7.4 (my truck is a 1993) - the line right off the manifold interferes with the compressor bracket, and in a big way. It's just not designed correctly. Maybe it fits on a 1994. I had to bend the hard line carefully and still had to leave a support rod out. The compressor is still bolted in fully on that big cast iron bracket, and the 2 support rods toward the middle of the compressor are in place, but the one towards the passenger side, I had to leave pushed out of the way even after bending the line. I'm not 100% comfortable with this and will be looking at other hoses or may possibly have a custom one made using my old hose as a pattern or even a donor.
Richard
