Anti-Afterburn Valve
Used on all 1968-71 models except for 1970 2M-B engine which uses an Air By-Pass Valve. When throttle is closed suddenly after hard acceleration, carburetor air is shut off instantly but fuel continues to flow momentarily which results in a rich mixture. To eliminate a backfire, anti-afterburn valve allows fresh air to be supplied to intake manifold which leans out over-rich fuel mixture and allows mixture to be burned normally in combustion chambers. Valve is controlled and operated by intake manifold vacuum.