Cool. Looking forward to pictures. I was thinking you were trying to make a 6BT fit.
Maybe you are aware of this already, for emmisions you will likely fall under the "hot rod" category so you don't have to meet current emmissions standards (I realize you used a `88 shell, but still worth mentioning - wasn't '87 the cut off?). I think you would need to meet 1980 standards (kids play).
Also, the diesel test is just a visual on particulates at idle.
So, you didn't have to start with an `88 shell to beat emmisions. Just throwing that out there. '88 is pretty much as good as any vintage to start with anyway.
If you want, I can sell you an 88-89 Limited with the engine and AC/HVAC still in place for $125 (what I paid). No axles under it, you'd need a trailer. I'm about 20 minutes north of Perth Ontario. (~4 hours away). If you have a trailer to pull with your Ram it might be worth your while so you can have a known original AC setup in front of you? I dunno if it works, but it is complete/unmolested. Some of the components are likely to be worthwhile. If you are interested I can take some pictures for you.