I installed them on my 57 3100 and they are on the rear of rotor. They work way better than the old drum brakes. Had a bit of issue finding where to get vacuum from. I have mine come from rear of carburator. It's equipped with a 350 and a 4 barrel carb. I would call them to make sure. Be ready to wait to talk to someone or have them call you back. I'm installing power steering from them now. Good luck, Grady
