Good morning,
The difference is the size of the rear brake shoes. It is either 11 or 13. The fact you have a 7.4 tells me you have a 2500 truck and they should come with 13 inch rear shoes. I attached a picture of the master for you from Rock Auto.
https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder
https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system
Roy
Caution: Brake fluid will damage electrical connections and painted surfaces. Use shop cloths, drip pans and fender covers to prevent brake fluid from contacting these areas.
1. On vehicles with manual brakes, disconnect master cylinder pushrod from brake pedal.
2. On all models, disconnect all wire connectors from master cylinder components.
3. Disconnect brake lines from master cylinder.
4. Remove master cylinder mounting nuts, then the master cylinder.
For additional information see Notes, Warnings, and Hints. See: Brake Master Cylinder > Fundamentals and Basics
Images (Click to enlarge)
Jan 11, 2021 at 5:17 AM
