The casting number posted doesn't come up on Inliners. Closest one is 3921968 (easy mistake to make) which could be either a 230 or a 250 from '64-'76 used in Chevrolet or Oldsmobile applications. The serial number from behind the distributor will be a better indicator of what it is and where it came from originally, as there is a possability it wasn't original to the truck it came from.
