Anybody know anything about C-60 Chevy's?

[k72516]

I saw this gem right near where I live. Can anybody give me info on C-60's? I know they obviously didn't have 2.5 ton axles, he obviously added those. But what about 4WD? I thought they all had those beefy dropped axles like big rigs. And big stake beds. Also, when I climbed into the bed to look in the cab, it looked really tight, as if the seat was pushed foward a whole lot. And lastly what kind of engine should this have, if he didn't swap it out. Diesel, right?

I'm gonna call and see what he's asking...

btw, the sign reads (if you can't make it out):

1975 C-60 2.5 ton military
if interested call 413-563-5521
serious calls only "street legal"