Collector flange position, the flange mount Hornies have a major interference issue with the T-bar crossmember. I was very disappointed at that. Probably turned out for the best though. 16 year old daughter runnin' around town in a '72 Swinger was questionable enough at the time, but with Purple Hornies on it? :wtf: was that Dad thinkin'? :rofl: From a looking back point of view. They do have the tube mount variety and a short bit of tubing from reducer with a kink in it would get past the crossmember.