My '88 F-150 came from factory with out A/C. What parts would I need to install an A/C system?

 

Did it to mine. The wiring is there, just one sub harness which is attached to the box on the firewall which you need along with the condenser, lines, compressor with brackets and the control panel from inside. If you look you'll see the compressor plug is already under your hood not plugged in.