I removed the rear brakes assemblies from a 70 Chrysler Newport and now need to figure out what they are. The inside of the drums measure 11" diameter. What I don't know is whether they are considered 2.5" or 3". The pads on the shoes are 2.5" but the flat surface in the drums are more like 3" wide. I am cleaning out the garage getting prepared to move and want to sell these but need to know how to advertise them. Thanks for the help in advance.

Are MORE LIKE 3" wide or they ARE 3" wide? A 3" shoe would have a braking surface that is a little bigger than 3" .

The smooth surface is 3" wide, definatly not more than that. If the 11x3 is more than 3, than these must be the 2.5"
I have a friend looking at these for his 69 Coronet and I'm sure these will work good for him but we wanted to be sure of it. He said he had the 11x3 off of an Imperial on a car once and was thinking he'd rather have the 2.5"s for this build.

Go by the shoe width, not the drum width...the 2 1/2" drum is close to 3" because they need a little "wiggle room" on either side of the shoe.