The changes made for accommodating the 4HP24 were not so significant that that they would preclude '03 and '04 models from your plan.

What would pose a problem is how you would deal with the the fact that the electronically controlled transmission is linked to the engine management system. This is the principle reason why you don't see people putting mechanically controlled DI transmissions in DII's.

I really can't imagine why you would want to even try to go down that route, using a DI transmission in a DII application? What with all the bad 4.6 engines turning DII's into expensive lawn ornaments, I would think it would be fairly easy to pick up a 4HP24 transmission obviating the issues you'd have with a DI 4HP22.

 

All the bad 4.6 engines is exactly why I have been considering this.

Replacing the failed 4.6 with the 3.9 that is carbed and distributer controlled, so the computer engine management issue, to my mind won't be an issue in this case.

 

Ok, I get you. Even still, trying to overlay a 14CUX system in a DII is an awful lot of work. The end result will be a much slower truck that will have a significantly lower resale value. You're in GA, why not just look for a really clean late model DI's. Considering the cost of a 3.9l, transmission, wiring harness, labor, ect you'd probably be better off with a '97 or later DI. You might even be able to find an LE or LSE which, while not quite as luxurious as a DII, gets you pretty close.