85 F150 4.9L electrical/vacuum nightmare

When I got the truck I noticed a lot of connectors, not hooked up in the engine bay. Truck came with AC but had been removed. So I guess my question is, how do I know what actually came stock as far as control modules and what is necessary? I'd like to remove any old outdated controls and make it as simple as possible. Starting with a vacuum advanced distributor, Just a few wires and the least amount of vacuum lines possible. Where does one start? I'm fairly competent as a mechanic but I'm out of my wheel house on this. I can read a wiring diagram, but with all the options, I guess I don't which one to utilize.

If you don't have a vacuum advance distributor you probably want to do a DS-II conversion.  Or, go with a one-wire dizzy.

Go to the Ignition Simplification tab on the page at Documentation/Electrical/Ignition.  Unfortunately we don't have the DS-II option fleshed out there, but the one-wire is.

To do the DS-II conversion you'll need a dizzy with vacuum advance for your engine.  But, before you buy one you should decide if you are going to run EGR or not.  The reason is that a dizzy set up for EGR will have lots of advance built in when the vacuum is high, and that will probably cause pinging.  So you need the right dizzy for which way you go.

And you'll need the DS-II harness from an earlier truck or aftermarket.  Plus you'll need the DS-II module, which will have a blue grommet where the wires go in.

pugster wrote

...a lot of connectors, not hooked up in the engine bay. ... So I guess my question is, how do I know what actually came stock...?

Post LOTS of pics, and we can probably tell you.  For each connector, describe the wire colors, and refer to the list on this page & the NEXT several: