you need to ground the a/c clutch relay on pass fender, just splice the relay ground wireand run it to the blower ground or to a screw on the fender
but with classic when you run a/c it wont increase the idle rpm and it wont deactivate with wot
to have it deactivate at wot hook a low psi (5 psi or so) N/C hobbs switch into the wire for ground and connect to vac source , when you boost the a/c compressor clutch will disengage