Rear drum brakes
Despite your ego, you are not always right. Ma Mopar was known for some oddities through the years.
My ego? Buddy you're the one arguing about a car that was 40 years old when you bought it being 100% factory original despite your complete lack of historical info on the car. If it was a '73 I'd say it's possible. A '74? Unlikely. A '76? Sorry pal. The factory TSB covers it. And that's not a factory brochure printed before production started, that's a TSB for the factory mechanics. If anything the date on that was probably later than the swap over actually started to cover any possibility of the earlier brakes being used. Sure, engine blocks were put into production years after they were cast, it's been documented. But your argument is that a bunch of later cars got earlier brakes years after the brakes were discontinued, and that you found several of them spanning several years? Those cars would also have needed to have the small ball joint UCA's. It's not a single part like an engine block, running those 9" front drums requires a 9" spindle, different wheel bearings, the small upper ball joint upper control arms that also went away for the '73 model year, all of it. Nope, not buying it.
I mean, I saw a Fiero with a Lambo kit at a wrecking yard once, but I'm not gonna say it came that way from the factory. Lots of things happen. Drag racers switched disk cars to drums back in the '70's because they thought the pad knock-back would slow them down. Guys pull disk brakes and later model K frame's from donors and roll their early suspension underneath before then send it to the scrapper. Happens all the time with the '73+ cars when they're used for donors.
So, once again I remove old drum. Measured the depth inside where the 2 inch shoes contact. Measures 2 1/2". Tells me these original drums are 11x2.5". Backing plate shouldn't be an issue. I'm trying to replace them because they've been turned past safe limits. I've ordered a couple 11x2 so in a few days I'll know.
The machined depth on an 11x2.5" drum is actually 3", so, if your drum measures 2.5" deep it's an 11x2", not an 11x2.5".
The only way an 11x2.5" drum will fit is with an 11x2.5" backing plate, it will not physically fit with an 11x2" backing plate because the 11x2" backing plate has a shallower offset back from the axle.
