After many years, finally building something for me, and not everyone else. Looking for options for decent small block headers, a nice 3 core radiator, and what aftermarket AC systems anyone may have used. Its a 1983 SWB D100 408SBM. 2 WD. Any suggestions welcome, just tying to get my ducks in a row here, and start grabbing more pieces. Thanks.

if originality is not important, i would go with a quality aluminum 2 core radiator instead of a 3 core brass/copper deal.
any more, my opinion is they work so much better, and are lighter as well.
just my opinion.
your mileage will vary.

To the OP: your PM box is full. I have a set of 2wd truck mounts for a 360 if that's what you are looking for in your wanted ad. I'm east of Dallas, Texas. Thanks.

Sending PM I think mailbox is fixed for some reason it reloaded all my old PMS from over 18 years ago!

Look up a company named Cold Case Radiators. They have the 26" radiators for Mopars with the two rows of 1" tubes like @Moparx mentioned above. Their radiators are built to accept the factory fan shrouds. They sell them in automatic and straight drive versions, with or without the trans cooler line hookups. As far as D series truck headers go, the best set I have ever had for an 80's truck were Hedman Tork Step headers. I had them in an 84 D350 with a 360. They came off the head with 1 5/8 tubes and then a little less than a foot out they turned to 1 3/4 tube all the way to the collectors. Unfortunately, I can't find them listed anymore. I would have liked to have had another set to go in my 88 D100 when I swap in the 5.9 Magnum. I just picked up a set of truck headers at Mopars at The Rock last year. Truck headers aren't as difficult to install as cars. You can almost stand back and throw them in! Good luck with your project!