1957 school bus panel

[75gmc454]

I have been looking for a truck to put my napco running gear in. A buddy of mine found a '57 panel 3/4 ton school bus. Has anyone ever seen one of these. It has two windows on each side that you can lower and raise like on all school buses. I think it would be a neat napco conversion.

Does anyone know the production on these 9600 gvw panels. It looks like a longer wheelbase than a standard panel. It has a standard interior code and a 725 paint code.

Any info would be a great help.