Along with the motor at regular operating temp, readjust all the still combination screws until the motor idles at the desired revoltions per minute with the highest possible manifold suction. As soon as that’s obtained, pitch the air-fuel mixture by readjusting the combination screw right a very small amount for each and every correction screw. That ought to be your suitable mixture setting. Take note: on this moderate small-block, our experts’ve achieved an abandoned setting of 18 “Hg.