Contact Skip at www.tsmmfg.com They make conversions for full size GM pickups so the full size Buicks would almost be the same or are the same. I did a swap on our site for a 70 GS455. Very simple and easy to install kit. http://www.buickperformance.com/rrdisc.htm
Mark Janis at Scarebird is a good guy. He was very helpful when I did the rear disc conversion on my Skyhawk. One bracket was wrong, and he DHL'ed a new one for free. Very responsive to emails. I actually used his S-10 brackets, and modified them to work on my stock rear. A few other guys were interested in doing the same swap; now he's making a bolt-on H-body bracket based roughly on the pics of mine I sent him. Seem to be well-made pieces. Designed to be a bolt-on using common calipers and hoses.
