I wondered if anyone has considered or tried using the RS headlight vacuum reserve tank for the dual purpose of running the headlights and also providing vacuum to the power brake booster. It sounds like one solution to low vacuum cam engines is to add a vacuum tank. Perhaps the hose size is too small or check valves are not designed for constant use. But it seems like you have a nice vacuum tank setup there that only gets used once or twice a day.

biggest drawback I can see is that tank and hoses and valve for the headlight doors is riddled with leaks usually. The hoses can leak at the headlight switch, the vac connections all thru the system.
That would put a vac leak in your system to the master. I have no real clue since thats not a part of the car I know real well but its a piece of your puzzle to consider maybe. Pozzi might have an idea on this. smile.gif

Shouldn't need to use the extra volume to boost the vacuum to the brake booster. The booster has a check valve that retains the vacuum in the booster. Obviously once the car is running the booster will get charged with the lowest (highest?)vacuum it sees while the engine is running. This would be during deceleration or coast. The check valve should hold the vacuum in the booster for weeks. If you pull the check valve out of your booster with the engine off and don't hear air rushing in then either the check valve or your booster is defective. I can pull my off after the car has sat for weeks, and still get a rush of air into the booster.

Of course this only works on the initial pressing of the brakes, if you pump the brakes then the vacuum assist is used up on the first stroke and the brakes will get harder and harder to press with each successive stoke.