[66Submarine]

I agree it looks like a '62, but that's an HO-52 Eaton; it's a 3/4 ton (20 series) truck.

BTW, nice truck. Doesn't appear to have been driven much from the condition of the interior!

Also, it looks like you have three factory 17.5" tubeless wheels and one wide aftermarket 16.5" on the truck; any chance the missing 17.5" came with it? I think those OE 17.5" and 19.5" wheels really look nice on these trucks. Nice find either way.