I just purchased a 1955 Customline with a 351 Windsor c4 Transmission, was wondering if the stock rear end will handle this. And was wondering what rear end it is originally? Any advice would be appreciated. Thanks:welcome: this car is also a 4 door.
If indeed that rear end is the stock 'as supplied' by Ford in 1951, it will survive only if you are gentle. It was built to handle 239 ci, 100-110 Hp and 150-160+/- lb ft of torque all put to the road on skinny 'un' grippy tires. In my distant past, I was able to destroy several with just a warmed over flathead and even more when I went to a 312 ci 'Y' block - but they were cheap then and I always had a couple spares along with at least one transmission. Minimum I would consider would be a Ford 8", even better a 9" of a good width and ratio. An 8.8" might be an even better choice, along with the disc brakes.
Station wagons had a Dana 44 which has been used in billions of cars and trucks over the years and parts are readily available.
The sedan rear is a Ford design, has a drop out center section and 12 spline axles. It will hold up as long as you don't dump the clutch and do burnouts everyday. You will likely break an axle if you install wide, sticky tires and drive it hard.
There are a few guys around town here that have '55/'56's with the Ford-style rears behind 390's and have never had a problem... and they built these cars in the 60's. But they don't beat the crap out of 'em either.
I'd run it until it breaks... then switch to a 9 inch.