6 The Load-O-Matic distributor is vacuum advance only and works based on throttled manifold vacuum (throttle position and load). The breaker plate is moved by vacuum and calibrated spring tension. Vacuum advance works against spring tension to advance spark based on throttle position and load. Calibration happens via the use of different spring tensions. Like most Autolite/Motorcraft factory distributors, there's one bushing and a barber pole shaft designed to bring engine oil to the shaft and bushing.