That's what i figured... was holding out hope for a 261 with everything else mismatched but i guess it wasn't meant to be...

Some other dimensions:
wheelbase: 137"

rear springs: 9 main x 2 spacers x 5 auxiliary 2" wide.
frame: ~7" tall x 2.75" wide behind cab.
wheels/tires: 7x18 8 ply tires. 18"multi piece dual wheels.

so....
1 ton frame
2 ton cab
1/2 ton engine

????

finding more and more bondo.... frown