Buick? No no lol thunderbird turbocoupe, my long term big hp turbo 4cyl project car. It's a factory disk rear, but factory 4 lug. I converted it to 5lug with sn95 axles when it was still under the bird, so I could run my cobra r's and mark 7 11" rear disks. I have to redrill the axles and rotors to get the 4.75 lug pattern.
If I was going to do anything else, I'd have searched for a 12 bolt or picked up a used gm posi unit and some decent gears for the 10 bolt. I'm not looking to make gobs of hp with the cutlass, just around 350-400 or so. I'm going to be using ported 58cc 305 heads to push my compression up. They're not the best option for heads by a long shot, but I'm out to prove something. I take on challenges people frown upon, like 305 heads on a 350, because I like being different and shutting some people up lol. But if you want a good rear for your money and have welding skills, the 87-88 turbocoupe rear is worth looking for. They're almost as strong as a 9", easy to convert to 5 lug and just as easy to upgrade the rotor size. Of course, that means the front needs help, to be logical. Haven't decided what to do about the front yet, but the stock brakes are going in the scrap pile, for sure. I want wilwood 4 piston calipers all the way around, for looks as well as vastly improved braking