Finally got my hands on a can of R12. Borrowed a set of R12 manifold gauges from a mechanic at work. Go to plug the gauge in... Different fitting. My car was converted to R134a before I bought it. This entire time, I thought it was R12. Took me a year before I found a good source for R12, finally get it, only to find out I could've grabbed a can of R134a and gotten it to work within minutes.
It gets better.
Grab some R134a and another set of manifold gauges from same mechanic. Started car, jumped the terminals on the low pressure switch (so the compressor engages... necessary to recharge) and start pumping it in. Get into the car, IT WORKS! Mmm, frosty. Go back to engine bay to get everything back in order. I heard a loud hissing sound. Not the valve.
Maybe the high pressure valve adapter is bad? Nope. Coming from the condenser. 90% sure it's the condenser.
So, anybody have a condenser lying around? I'd prefer one that doesn't have holes in it, because I already have one of those models.