disc brakes

Does anyone know why disc brake E and B body cars have 10 inch rear drums and not 11inch.im using 1970 as my example.also has anyone tried switching to 11 inch and what where the results.thanks.

My brother thought he would upgrade his Challenger to 11" rear and then had to add a proportioning valve because the rear brakes were to aggressive.

The trans am cars have rear 11’ brakes. I’ve had my rear brakes lock up under hard braking on my AAR. That’s not good.

Put the 11.75 rotors up front and then put the 11 inch rear drums out back. You'll notice the difference. I had that setup on my early B body and it felt like you hit quicksand when you stood on the brakes. The car just dropped down and stopped.

thanks fastmark thats interesting that the factory used 11 inch rear brakes on the t/a cars.i had assumed up until now front disc could only be had with 10 inch rear.

For what its worth, those 11" rear drums (finned) are very heavy in mass weight vs the non-finned 10" small drums.