I was having a hard time with a low gear ratio and poor brakes on my 47 P15 Plymouth. It was time for a trip to the wrecking yard so off I went. I was really looking for a rear end for the car to get my gear ratio to about 3.5-3.73 to 1 instead of the 4.11s that are stock for my car. I have shorter than stock tires on the thing and that makes it even worse. While looking at a rear end in a 96 Ford Explorer I noticed that the rotors and calipers might make for a good swap onto my car without too much expense or effort. I went home that day with only ideas in my head and some measurements of the rear ends (drum vs. disk) in the Explorers. Oh and a few pictures of how the front brakes are mounted etc... A day or two later I went to a yard out of town due to a much lower price and found that the rear end they had (with disks) was a 4.10 gear ratio so instead I took home the calipers and rotors off the same rig. This is where I started.