Anti-Backfire Valve

Used on most 1966-67 models. When throttle is closed suddenly after hard acceleration carburetor air is shut off instantly but fuel flows momentarily which results in a rich mixture. To eliminate backfire, anti-backfire valve opens momentarily to allow clean air from air pump into intake manifold to prevent a rich mixtures from occurring. Opening of valve is "triggered" whenever there is a rapid rise in intake manifold vacuum. Opening of this valve also prevents rapid reduction of engine RPM, which eliminates necessity of dashpot.