first number is a general category [3xxx= "light trucks"], 2nd is weight & length, 3rd number isn't used much but usually related to the last number which is body style - yours is a 3604, a 1/2T short panel is 3105, etc ... see the resto pack for a run down

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics