Doing some work on the cutlass And decided to start looking at casting #'s. Intake is W, 74 455? one exhaust manifold 17, 81-85 350? Other exhaust manifold 1? 350? G heads? block is 396021F, 455. block Id starts 30C 70 455 California? And its all in a 71 cutlass block vin does not match the car. Any way I am putting a performer manifold in with hooker headers should breath better than those mismatched parts

 

Who knows what happens to cars over a 40 year period and multiple owners.

 

Well the headers shure will.