Be aware that a 57 Dodge and a 55 & 56 are different critters. The 57 was "all new" and the power steering on a 57 only fits a 57-60, and leaves a lot to be desired. The steering box is part of the steering column, (both manual and power, but the power box is huge) and it all goes in and out of the car through the car's interior. Because of the 57's torsion bars and the location of the steering box, you are very limited to other power steering options. Something you may want to keep in mind as you look for a car.

We installed an 8.8 into my son's 57 Dodge wagon (along with a 5.7 and its auto trans). The 8.8 we installed was a disc brake with a 3:73 limited slip. it was originally a coil spring rear end (I think) out of an Explorer. The wheel track was pretty narrow for the wagon, he had to get wheels with the proper off set. We also had to cut and open up the drive shaft tunnel about an inch for driveshaft clearance (I believe it was because of the driveshaft diameter rather then the pinion offset, but it was several years and several builds ago.