Sorry I didn't get back to the question sooner. Won't help any though, I have no idea. It was a dupont custom mixture though. The truck has been painted since 2009.
It's been a while so here's the update:
Glad to report after a carb rebuild everything is running right. I swapped out the Distributor for an MSD Billet model. That one that was on there was crap. The timing advance gear/weights broke and the shaft would spin freely.
Also tightened all the belts up and cured my squeal. I feel like an idiot for wondering what it was. It had some other oddities about it that led me down the wrong road.
The tranny is kinda funny. It want's to shift well above 5k rpm at WOT which doesn't feel comfortable with this engine so to get it to manual shift I have to briefly let off the gas while upshifting and then it'll slam you back when it hits. Guess the shift kit is doing it's job but the modulator pin may be a bit too long keeping the tranny in the same gear too long. I can live with it since there's a method to shifting that seems to work 100% of the time.
On a comfort note,
I insulated underneath the cab to keep some heat out which helped. Some of it was too close to my header/exhaust connection and melted off. Whatever stayed on I just left on and what started falling off due to excess heat i pulled off. Still better than it was before. Then I sound and heat insulated the entire cab floor, inside the doors, and behind the seat. Keeps things a bit quieter inside and some heat out. Just got some custom molded carpet with heavy sound and heat insulation on the bottom that should keep out the rest of the heat and more noise.
I had the rear end swapped out for a 3.25:1 with an eaton limited slip. Does the job pretty well and gives me better city mileage than that 2.50:1. got about 7.3 mpg on the last tank with some playing around. I could probably manage 8.0 if I keep off the skinny pedal.
Power steering pump crapped the bed and drooled all my fluid on the garage floor. Changed it out.
Except for the mileage it's turning out to be a pretty reliable build that I can drive once or twice a week to work.
Here's a recent snapshot: