Could be, The number is not a truck number. But block casting numbers for light trucks are not truck specific. It reads as, D9=1979 A=full size Ford, F=? I bet its a E and that =engine. This casting number would have been used for any 351W in any Ford, Mercury and Lincoln car and light truck. Look at casting numbers for the distributor, intake and exhaust manifolds. they may give more clues as to were it came from.