if you have a part #, you might try to cross reference it on RockAuto. Or, try a brake and clutch svc shop. Here is Seattle, there is Brake and clutch supply, they do a lot of big stuff, as well as reline shoes, brake bands, etc.

Mike
1955 Chevy 6400 ex-flatbed (no bed now!) sold September 2023
In the Stovebolt Gallery
1958 Chevy 6400 flatbed W/dump
In the Stovebolt Gallery
1959 Chevy Suburban Owned for almost 20 years, Daily Driver -- sold May 2016
In the Stovebolt Gallery

Sufficient unto the day is the evil thereof