Well, this may be impossible to find out. I looked for the serial number on the engine and it is not there, the only numbers on the engine is the casting number on the block (3835253). I also got in touch with the guy I bought the truck from. He doesnt know much history about the truck either. It was his grandpa's and no one is around anymore that would know any thing about the truck. Is there anywhere to find a spec sheet of this truck when it was built via the Truck serial number?