Should be on the plate centre of the bulkhead(firewall) inside the cab. If that's missing then see the right hand front spring shackle bracket. Nice truck love the colour LOL. It's a 107 if its a 54 and has the early horn button on the centre hub ( don't Break it ). It should do up pretty well and end up looking like mine. Are you going to do a full restoration or get her mechanicaly A1 and leave the original patina. I will post a pick from the Workshop manual about the numbers.
Mike:)

