Hello Everyone,
I have a question. I am putting an early 1980's rear axle w/disc brakes in my 1955 Chevrolet. I am wanting to change the gear ratio to around a 3.73. Is my rear end carrier a 7.5 or a 7.625. Do both of these carriers us the same ring gear. I have noticed that most ring gear and pinion set list the gears as the same, but the carriers are different. Any help or information would be great. Thanks.

Uh oh......
Are you putting a 'Cadillac' axle from a full size RWD into your Chevy?

These axles are different from other GM rear axles, and ring and pinion sets any better than a 3:1 are very difficult to find. These rear ends are NOT the regular GM 10 or 12 bolt items that GM used for most other RWD cars.

You will also find the wheel bolt spacing is wider than for your '55, so the rims will not fit.

Also, isn't the axle too wide for your '55?