A PCV valve is a vacuum-controlled metering device that regulates the flow of crankcase fumes in the positive crankcase ventilation system by allowing more flow at high speed than at low speed.This valve acts as a system shutoff in case of e ngine backfire to prevent an explosion in the crankcase. It is recommended to replace your PCV valve during every tune-up Camaro applications:1967 283Chevrolet / GMC Truck applications:1963-65 all V8 Impala / Full Size applications:1963-65 all V8Chevy II / Nova applications: 1963-65 283 (threaded type)1965-67 327 (threaded type).
