I do believe that my 77 Ramcharger started life as a 400.
I havn't seen those flares anywhere before. The paint job looks age correct.
Cool looking truck.
If you purchase the truck and need the front axle, transfer case and the correct rims to convert it over to a 205 or 208, I have all the parts you need. Not just as simple as the transfer case. You must change a few things. Let me know, I can cut a real good price.
Looks worthy of purchase in my opinion. The black interior seems to be a hard thing to find. Mine was brown originally. The trailduster I have is blue inside.