Brake vacuum canisters

I tried a few cans years back with mixed results. If your vacuum is really low & you can't live without the power brakes, then yes it will help to some extent.

If your in the 9-11" vacuum range, your driving style will make as much difference as a storage can. Any engine will build decent vacuum on deceleration, but it's limited in quantity at the booster. A stop here & there are usually fine, But if you do a lot of stop and go city driving, or brake pumping, not so good...

Make sure you're running your initial ignition timing at the peak it can handle? The difference between 8* & 15* can make a big difference in idle vacuum, and the resulting brake performance.

Good luck, and keep us informed.