Corvette Engine Type

Hey all,
I just bought a 1967 Jaguar 240G that has been modified with a 454 10.25 compression chevy enginre... anybody have any idea what year Vette this is out of? I'm restarting the engine after 15 years and it would be easier if I could pin a year on it. Picking the car up Sunday 9/19 and can probably get a number off it, if that will help. Thanks in advance for any input..
chuck

update : after a little more research I found its an oval port with holly carb.. I'm guessing 71 to 74... picking the car up tomorrow : ) and I'll try to get the casting #