I was going to sell this '70 Sedan Deville for $200 to a guy. I originally bought the car to get the 500bb and 400 tranny out of it. I had a gut feeling that I should take a good look at the rear end before I let the car go. I had a double take. I looked under there and started counting the bolts in the cover and would you believe it, 12 bolts? I was under the impression that the only Cadillacs that came with the 12 bolt were commercial vehicles such as hearses and limos. Are all of the 12 bolt GM rears mechanically the same (other than ratios) or are there a few variations that aren't as good? I want to retro-fit this one to a 1980 or 1988 Brougham. I noticed that the trailing arm brackets and shock locations look different. Time for cutting and welding. Also, are the 1970 Sedan Deville rears the same width as the 1980-1990 Brougham? What about using the brakes off of the Brougham on the 12 bolt? Can I get gears for the 12 bolt that will work well with an OD tranny (200r4). Is all of the effort worth it in the end.? I plan on building at least a 450hp pump gas 500bb.