the heater 'boxs for ac and nonac truck are different, the quick and easy way it to pul the compressor and leave the box, heater will still work no problem.
i swiched to non ac in my burb, buy grabing the non ac system out of a junker, including the controls and every thing, i then sazalled the fire wall around the heater box, and mounted it on my fire wall and sealed it in place ( the holes in the firewall are different) this pluged my old hole and showed me where to cut the new ones then i just bolted the heater boxs on and hooked up the controls.
the only real problem is that it left 2 smal round holes open, and the power wire for the fan that goes to the swich did not click in to the original conection behind the dash, but i just sit it in there and it stays so its all good