1972 prototype dodge truck?

so far what i can gather is this: the truck was a pre production and specially optioned truck for show use from the factory. the guy that bought it from the chrysler executive got it around 1980 and he did a custom restore and turned it into the "big red express truck". it originally came with a 400 and when the guy re-did the truck, he put in the 67 383 magnum. it was originally white and he repainted the truck the red which is how it sits now. using the puzzle pieces i have, this is my theory as of now. i have the guys name that re-did the truck, and im going to try contacting him so i can get the full story on it. he will probably have a lot of pictures of the truck back in the day, so hopefully i can get those too