Replacement vacuum advance can for 318 distributor

Gentlemen,
Vac can on my 318 distributor broke. Trying to find a replacement, would be great if I could find one that fits at an auto parts store. Currently the arm is marked 10, its a 2642718 distributor spec sheet says 10.5-13.5 distributor degrees at 15" vac.

Distributor is on a nice warm 360 with cam, exhaust and intake, so I wouldn't mind a little less vac (thinking maybe 8 distributor degrees?) so I can run more initial timing.

What are my options here? I tried to swap cans with an electronic ignition distributor and the arms were a very different shape and not compatible.