Well, I just found out that my motor mounts, which were alleged to have been replaced during my engine overhaul, were not, and all the mounts and vibration dampeners are completely shot, the engine is sitting right on the frame, which is why I could never get the engine to stop shaking the car. Additionally, the vaccum modulator on the trans was never adjusted after the rebuild, which accounts for my slipping transmission shifting.
Also confirmed that the a/c compressor was never installed (lubricated) properly during the R134a conversion, which is why I only got 19 miles out of the new compressor.