HMMmmmmm---Both of my one tons (a '76 W/454 and a '74-'79 blend W/355)weigh in at around 7,800 pounds each,but they're duallies with 12 foot flatbeds and tool boxes,too. I'd never thought much about why they're so heavy,but now it makes sense.
Speed

1954 GMC 350
1957 GMC 1/2 ton
1962 Chevy C-30
1952 Chevy 6400 dump bed project truck
'98 Harley FLSTC
'66 Pontiac Catalina
'76 Chevy 1 ton Duallie
'84 Bronco II
'78 Dodge W-200
'81 Toyota 4X4 truck