We use GTS Customs extended rear quarters on the cars we do. We just finished a 63 that has a SR3 chassis, zo6 engine and suspension and C4 in the back. It was at Barrett-Jackson in Vegas last month. It's back in here to have the 6 speed pulled - and a 4L65E with electronic shift installed. The guy who we built it for was in a car wreak and can't push the clutch in any more.