I know this is a super-old thread, but I am coming to the same issue and can't find an answer anywhere. I am swapping a 3rz into a 1986 truck that has AC, but it doesn't work even though it is complete. No idea why as I haven't tried to troubleshoot it. Has anyone swapped a 3rz and kept AC? R12 or R134? What compressor setup did you use and did you swap the pulley?
