Yes like I said, if you were to build a custom chassis that would support the weight of the engine along with the abuse you will put it through as a mud truck, you would be alright. Along with the body mods. I built a chassis for a friends '63 CJ5 since he is putting an EFI 460 in his. Used 2"x4" .120" wall tube for the front and rear arms of the frame, and used .188" wall for the middle where it drops down.
Also, seeing as it'll be a toy, making it pretty goes out the window and makes the project a bit easier.
Are you in Ontario Canada, or California?