The center carburetor arm is installed next in the same manner. It is placed at the same 40-degree angle as the other link arm. The torsion spring is set in the same manner as the front spring. For this installation the center carburetor arm is a custom-built piece from SO-MO. It has multiple adjustment holes for the actuator arm of the linkage, which allows a change in the linkage geometry for specific applications. This affects the rate at which the front and rear carburetors open in progression with the middle carburetor. This custom arm extends below the throttle shaft for connection of an automatic transmission kick down or (TV cable) cable. There is a pin with a button head screw to hold the cable slide arm in place.