I installed TTI Headers and exhaust system on my 72 Demon (check out link below). I used the original hanger location. My car was an original single exhaust car so it only had a hanger bracket on the driver's side (same bracket used to attach brake line). I purchased a new hanger bracket for passenger side and mounted it in the stock location.
http://www.forabodiesonly.com/mopar/showthread.php?t=97994