If there's room for it, like on a 1-ton or bigger truck, try mounting a retired 30-lb. Freon canister somewhere under the frame as a vacuum reservoir. Use a 1-way check valve in the vacuum line from the engine to the tank. I just drill a correct-size hole in one end of the tank and install the stock rubber grommet and check valve from the booster I'm using, creating a double check valve setup- - - -one from engine to reserve tank, and the original one at the booster. If you're using a vacuum-shifted 2-speed rear end or vacuum wipers, the reserve tank smooths out the operation of those systems, also.
Jerry
