cleaning out some of dads parts collection since 1966. I've got a really nice exhaust manifold here that was removed from a 350 HP, 1970 corvette in the mid 70's. he may still have the mate to it, but I haven't finished my search. grandpa started the shop in 1919, and much has been accumulated since. this has a date code of A60 (JAN 197O). no reproduction junk here. 100% authentic GM. all three studs are good for the exhaust bolt-up. this casting number was used from 1964-1967 on the 300hp and 350 hp 327 corvette engines, and then again in 1970-1971 on the 300hp and 350hp 350 engines