CARBURETED Models

In order to meet Federal emission standards at all altitudes, all feedback carburetor vehicles are equipped with a high altitude compensation system. The system consists of a High Altitude Compensator (HAC), passages for additional bleed air and additional jet air and a vacuum delay valve (Auto. Trans. vehicles). As altitude increases, air pressure decreases and the air/fuel mixture becomes richer. The HAC system supplies additional air to the primary main well.