As far as wheels go, your best bet is probably
Sourkraut's Model Trucks - Wheels. Chris sells wheels by Mo'luminum, Plaskit & Kit From Services. I believe the tires in the L700 kit are 10x20, but you could always use other tires as well.
You're on your own for the engine. I know very little about street rods & suped-up cars. The engines Chris sells would be too big for the Dodge. A 600hp Cummins would basically destroy the frame!
Good luck with the doors. I still can't get mine to fit, and I'm just doing OOB!
Jim