If you study the specs on the GM heritage pages you will find that the GVWR will change with different size and ply of the tires. Maybe that is what was keeping the rating lesss than the spec plate states.
1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy
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