These heads came off a 1973 Corvette 350. Casting number is 330545 and the date code on both is K202 which is November 1972. They have been cleaned and magnafluxed and are ready to be built. They are factory 2.02 intake and 1.6 exhaust valve with the screw in studs and guide plates. All oe and have not been machined. They will work on any sbc 283-350. 76cc combustion chamber