Speaking of rears with disc brakes, I found this on craigslist:pontiacgp said:I have the 67 chevelle rear and like JBrue said it's more narrow than the 68 and up...it's 2.5" wider than a G body rear and 2" narrower than a 68 and up A body...I'm currently putting disk on the back and it looks like an F body calliper bracket with 1980 Seville rear callipers with the parking brake will work...I just have the get the flange on the axles trimmed to fit into the F body rotor
http://indianapolis.craigslist.org/pts/2358904317.html
It got me interested but it's a bit of a drive from where I live. If anyone else wants to jump on it, go ahead.