High Altitude Compensation System: Description

The High Altitude Compensation (HAC) system is used on California vehicles and high altitude Federal models. As altitude increases, air pressure decreases and the air/fuel mixture becomes richer. The HAC system supplies additional air to the primary main well.

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).