How do I tell a ton and a half from a 2 ton?
 

I was just given a 1946 Chevy farm truck by my Uncle. How do I verify the year and tell weather it's a 1.5 or 2 ton?

Also, where's a good source of parts for these things? I'm sure the cab and electrical etc. are the same as a pick up, but I'm referring to stuff like the trans, differential, brakes etc. Thanks.