Circuit 1 4 Position switch in the cabin (no flex fuel). Position 1 E85 High Boost Position 2 E85 Low Boost Position 3 98 High Boost Position 4 98 Low boost   Circuit 2: Uses a rotary potentiometer in the cabin (no flex fuel) E85 with variable boost (0-100% boost) 98 with variable boost (0- 80% boost or whatever you desire)   Circuit 3: 2 position switch in the cabin (utilises the flex fuel kit) Position 1 Flex fuel with high