If you have that factory wiring diagram, you can tell which wires go from the plug that went to the plug that plugs into the Lean Burn, pick out the wires from that plug (or those 2 plugs, if yours has 2 plugs) that come from battery hot w/ key, go to the 2 wires that go to the "RUN" pickup in your current distributor, and (I think) one side of coil (one from the "RUN" pickup goes from distributor to other side of coil) and leave the rest of wires in the plug(s) to the Lean burn lie, or pull those out of harness. Your choice. Take those 4 wires, cut from the plug(s) going to Lean Burn computer, and splice the respective wires from that plug to the 4 wires in the pigtail that you get, that plugs into 4 pin ECU. There are multiple line drawings available via Google search that detail the wiring "to" the 4 pin ECU. all of those are in the harness already. if in good shape you can just use what is there. the wiring to the dist and the coil. you dont have to run redundant wiring but you can.
There is wiring to lights, wiring to sensors, wiring to alternator in the harness that you will still need, as they are.
get yourself an electronic ignition distributor from a 1973-1980 slant 6 with electronic ignition, (it will have the vacuum and centrifugal advance that you will need)
talk to member Halifaxhops he has many rebuilt distributors for Mopars available, he's popular here. He's always in classifieds both here and that truck forum, hawking his goodies. That and a carb from same era that has teh nipple for ported vaccuum to run vac advance and you are set. Not difficult, just takes a bit of time.
As an aside, IF you can find a super 6 setup (2 barrel carb and intake) that would be perfect time to upgrade/ IF you want to. Just a suggestion, not mandatory.
