lean burn

yup, my 85 with a slant 6, had 2 pickups in the distributor. but I also had an 81 W150 years ago with a 318, factory 4 bbl, and plain 4 pin electronic ignition. That truck also had 2 pickups in distributor with vacuum advance, which your slant will not have, because those functions have been moved to the brain box. My 81 had a relay somewhere among the wiring harness to differentiate the start/run functions of each pickup.NO lean Burn on that truck.

You don't have to pull all of the unnneeded wires to the Lean Burn out of the wiring harness, but you can. It would make for a cleaner job. I'd untape it and have a wiring diagram right next to me and go at it. There is a splice (I think blue wire) with 3-4 wires (all same color, it's around the area of the back of the brake booster in harness) going every which way, that comes off the "hot with ignition in run" position. goes to ignition box (or lean burn), choke, and anything needing "hot with key". I think you can trim a couple of those away. There is also a connector many call a "duck foot" with 1 "hot" from the battery splitting 4 ways, along teh driver fenderwell between the battery and hood hinge that needs a close look at. Most of the fusible links join within that black rubber connector. this connector is not able to be pulled apart, unless it is either shorted and burnt or cut apart. if it is OK, you do not have to mess with any of those wires in doing your conversion/// but it is a known trouble spot in these wiring harness, that needs inspection.
the factory service manual shows wiring for both options. (ECU and Lean Burn) I wound up getting my factory service manual from Ebay.

I think 99% of 81+ slant powered trucks in US, had Lean burn from the factory, the 318s (besides California) still had 4 pin ECU til 86, when they went to Lean Burn. 360s all the way til 88 could have come from the factory with 4 pin ECU (and no Lean Burn). Canadian trucks and Mexican trucks a lot more "lenient" with emission BS. which is why service manual shows wiring possibly going "either way" in any given year. some years Lean Burn was on air cleaner, other years it was behind battery within fender.
In my case, my wiring was hopelessly butchered by the past owner. It was a mess. (and that is putting it lightly) I won't get into detail here in this post. I found an 84, 360 1-ton truck (least emissions with heavier GVW truck) in the junkyard with a wiring harness in much better shape (though not perfect) as compared to my original harness. not neccessarily looking for that combo, but "I got what was there for the taking".
It already had ballast resistor and 4 pin ECU wiring, not Lean Burn. Plug and play. I just had to extend a couple of wiring pigtails, mainly the ones going to the coil the distributor and the oil pressure sending unit, but not by alot, taking a V8 harness and making it work on a slant 6. like 4 wires that needed lengthened. Ballast resistor, ignition ECU box, voltage regulator, etc mount in same location on firewall, regardless of engine. Alternator wire length worked out fine with V8 harness on my slant 6.
I did still untape that junkyard harness and check the wiring for damage within (brittle insulation just from age) and retaped it.
I modified my wiring from stock, I did away with all the fusible links and added an underhood fuse box from a newer truck (wasn't from a Dodge product, but wiring is wiring) and ran everything that used to be run thru a fusible link now goes thru a large blade style fuse ("Maxi fuse") included in said fuse box. I have other threads spread among the forums, that I could possibly link (if I can figure out how) that details what I did, and I have a hand drawn diagram detailing which F.L. went thru which fuse holder.... I need to scan to the computer, so I can post it or PM it to interested people....
There is another option, many switch to a GM HEI system on these trucks to get around Lean Burn.... no harder than going to factory Mopar system and you dont have to worry about wiring in ballast resisitor...... go look on slant 6.org.... lots of talk on teh subject there, probably some mention of that option here too, with a search.
Lastly, some of this goes way beyond what you will have to do just to convert your ignition... but still needs to be considered. Wiring is one place that is too important to hodge podge or butcher..... I sure dont want my truck to short out and burn to the ground so I don't do shortcuts in that department. The PO of my truck sure did though.... I had alot of "undoing" to do.

BTW, this is the guy that you met in the campground, and got your gas tank from.......