Brake shoe part numbers are different but I don't recall if the shoes will or won't interchange at all, or interchange one way but not the other, or if there's a part in there, possibly associated with the parking brake that doesn't interchange.
The 1973-1975 A-body, and others, rear 10"x2.5" brake shoes use the Friction Materials Standards Institute (FMSI) number 333. The 1976 A-body, 1976-1980 F-body, and others, rear 10"x2.5" brake shoes use the FMSI number 445.
The linings themselves are the same. The metal shoes differ primarily in the attachment of the parking brake actuator lever. The following images illustrate the differences.
Most 445 shoes, except early production, can be used in place of 333, but not the opposite unless the park actuator levers are changed to match. The outer set of shoes in the following image are number 333 and the inner set of shoes are 445.
The following two images show the 445 shoe has a trapezoidal shaped lever hole and the 333 has a round hole. Note that this 445 shoe has a combination trapezoidal and round hole to accommodate either style ever. Early production 445 shoes did not have the combination hole.
Note that the 333 shoe in the foregoing image has an extra hole compared to the 445 shoe. This is to accommodate different spring lengths for the leading shoe. Some shoe stampings may differ.
The following images shows a 333 shoe and matching parking actuating lever with the horse shoe clip and spring washer to mount it and a 445 shoe with matching parking actuating lever which loosely clips into the trapezoidal hole.
The following images show both the 333 and 445 with the earlier parking actuating lever attached (without the horseshoe clip secured allowing the interchange of most 445 shoes for 333 shoes.
NOTE: A similar comparison can be made for the 11"x2.5" shoes, FMSI number 335 for earlier models vs. 11"x2.5" shoes, FMSI number 446 for later models.
