Mr Gasket makes these & they are intended for power brake boosters on cars with big cams.
Has anyone ever tried using one with the vacuum headlight doors when the OEM unit failed?
If you can’t find a used OEM one, I don’t see why not, it looks a little smaller than the original.
www.google.com/search?client=firefox-b-1-d&q=Mr+gasket+vacuum+brake+booster+canister
I had a '67 with a huge solid lift cam. In my car there was insufficient vacuum for the power brakes. I added the Mr Gasket can because it was supposed to help the brakes. It had little effect. The headlights always worked fine with the big cam because the factory vacuum tank is tied solely to the headlights and is isolated by a check valve from the brake booster.
I would simply find a good original one in your case. They are inexpensive and easy to find.