I’m installing new brakes on my 57 Chevy NAPCO project. On the rear backing plates there is a steel piece that appears to work as a retainer for the wheel cylinder boots. The replacement W/Cs are too wide by almost 1/2” so they don’t fit between the part on the backing plate. The new part #s are Carquest EW 13387 and EW 13388. I have a couple of old Delco cylinders with a casting # of 5450629 that are the right width, about 3”, but they are too far gone to rebuild. I’ve replaced the brakes on several Task Force trucks, but I’ve never had this problem. Any thoughts?

Thank you,
LJ