If you Google "1989 454 smog pump and ac delete" you'll find several engine specific articles and/or vehicle specific forum posts about re-routing your serpentine belt, and the need for "delete pulleys" to make it work. Did that on my old '90 F150, and the Mustang forums had everything spelled out. You should also be able to check out your sensors with a good VOM, but you may need a variable DC power supply to dial in low voltages for some, like 0-5VDC. Just need to research the input/output signals for each one first.

Should be a cool old truck when you're done!!