My 1982 E350 is considered a "one ton" van.
Yes.
The Ford E-350 is a one ton van and the Ford F-350 is a one ton pickup truck
yup
Yes
A half ton.
Typically, 1 ton fords had either a 351 windsor or a 460.
Yes the half ton is a 150 and the one tone is a 350.
3/4
probably, look in your manual.
A Ford F-250 is a 3/4 ton truck ( Ford F-150 is 1/2 ton / Ford F-350 is a one ton )
Yes
Check owner's manual. If you don't have one copy and paste link below; www.fleet.ford.com/maintenance/owners_manuals