8.5 rear end

I bought my 64 valiant that had its rear end changed. I is a posi traction 8 1/2 seems to have 3.23 or so gears in it. I pulled the drums to install new brake shoes and they seem only 1.5 inches wide where I believe the factory rear end had wider shoes. My question is what is the most common source for this rear end that people used so I can try and figure out what model mopar brake shoes I need to buy. Any guesses??