Need to think carefully about how you plumb that one. What worried me is the pump fighting the manifold vacuum, though perhaps I am wrong (?)
If you tee the vacuum line (one leg to the manifold, one leg to the pump, one leg to the booster) then this can happen:
a) the car is at idle. Butterflies shut, lots of manifold vacuum, booster is happy, pump is shut down.
b) Car is running at part or full throttle. Booster is not happy. Pump starts, but has to suck down both the booster
and the manifold. The manifold is huuuuuuungryyyyyy.... the motor has an infinite ability to deplete vacuum. The poor old pump can't keep up.
The line that goes to the manifold needs a check valve. It will let the manifold suck down the booster, but if the vac pump tries to suck down the manifold then the check valve shuts.
So what you end up with is two check valves - one in the leg to the pump, and one in the leg to the manifold (i.e. you cannot rely on the single check valve that lives in the face of the booster).

- booster check valve.png (26.65 KiB) Viewed 416 times
Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.