No, it won't work for your brakes the way it is plumbed. It does have a check valve, but the line between the canister and booster is open to the intake. You would need to add a check valve before the " T " fitting and remove the one on the canister before it would do any good on the brake booster. It's a reservoir for the vacuum wipers only. The lines coming back out of the canister are not big enough to work with the brake booster, or should I say big enough to act fast enough on the booster. Booster need 3/8" line and fittings.
Typical vacuum on a stock engine will be around 18 to 21 inches. My 250 will idle around 20 inches. On a long down hill with no throttle opening, the vacuum can go really high, pegs the gauge, of course it goes to zero at full throttle, 1 to 2 inches at full rpm and full throttle.
