For starters it would have be an E-F or G 440 HP block & have the partial vin# of a V code car stamped in it,but lets say the supposed 440-6 block came out of a 71 Jensen Interceptor SP that wouldn't have a vin# stamped into it then what,if its just a bare block you would never be able to tell the difference, if its a complete bottom end that's never been rebuilt you could determine if its a SP eng.by the specific SP internal components & that's about it,there was about 200 Jensen SPs made so there could be some engines around.