Mike,
You are a little late with the ideas... I considered the Cummins, and other body styles, and even other makes of trucks. And of all the choices I decided the best ones for me are the AD Chevy, DD 4-53T, and RTO-6610 Roadranger.
I am not switching body styles now just to avoid a little sheat metal fabrication, if it's not that it would be some other problem with a different model truck...
Had the idea for the whole truck, and most of the details worked out even before I had any parts, engine, trans, or truck... The plan is for a 48-50 Chevy 2 ton, 5 window cab with no rust, and I'll stick with that.
I like the AD Chevy's much more than any other years. I bought the engine for this conversion long before I even found the perfect truck for it.
There's no going back now,
Grigg