Let us get back to the original subject of this thread.
If you have a dual action fuel pump, the vacuum assist is designed to provide vacuum for the wipers when the engine vacuum is low. This is usually when going up a hill with the throttle wide open. The pump assist provides the best assistance when the rpms are up. At low rpms and high engine vacuum, the pump provides less vacuum than the engine and the engine vacuum pulls through the pump. The draw side of the pump should be hooked up to the wipers and the other side connected to the manifold.
