My 1975 F150, 390 original A/C truck, had the coil mounted on the compressor mount. I looked in the MPC, the ignition diagram doesn't show a A/C position, just a non A/C position, which is the usual mounting on the intake. But the dealer installed diagram shows the coil going on a A/C bracket.
My buddy bought this from the original owner in the 90's and that's the way it was when he got it cause I thought it was strange, my buddy thought maybe it had something to do with heat since this puts the coil out there in the airstream of the fan.
Keith