My recall is that the drums are the same front to back but the shoes were different sizes. When I had my 57 Pathfinder I had converted to a dual pot master and split the system front and rear and used the larger front shoes on the rear as I had included a proportioning valve.
My recall is that the drums are the same front to back but the shoes were different sizes.
Yep.
Front and rear drums are same 55-57 Chevy (and Canadian Pontiac).
Brake shoes are different (2" front, 1-1/2" rear).
Good drums have no grooves inside, and are same inside diameter full width (no "lip" at the outer edge). Nice and smooth inside. Maximum inside diameter 0.060" larger than stock - per factory manual, they can only be turned once:
You ought to be able to tell by the outside edge if they have been turned - if it looks like unmolested original metal, then probably not been turned. Or, measure all of yours inside diameter, and the smallest is probably a good starting point for original.
Dave
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1956 Pontiac Pathfinder 2dr sedan, 496 - dyno'd 545 hp, stick shift, 4.11 posi - Hot Rod
However, if you only need front brakes, it might be a good time to upgrade to disc brakes. They give WAY better stopping power than the old drums. Here's the kit I used (included 2" drop front spindles):
Cost under $500 US, delivered (shipping for heavy weight is not cheap).
Dave
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1956 Pontiac Pathfinder 2dr sedan, 496 - dyno'd 545 hp, stick shift, 4.11 posi - Hot Rod
1956 Pontiac Pathfinder 2dr sedan, 496 - dyno'd 545 hp, stick shift, 4.11 posi - Hot Rod