Brake pedal is really stiff

You lucked out because I am just now upgrading the 9" drum brakes in my 64 Valiant. Parts from rockauto.

The rear calipers are Raybestos WC34876 (x-ref Bendix 33504). They measure 0.810"D bore = 13/16"D.
The front calipers are Bendix 33242 and Centric 134.63008. They measure 1.00"D.
These are the same dimensions that rockauto lists.