Early A-body Spitfire headers

Did the Dodge Dakota Headers ever work correctly? I was considering grabbing a set of those and trying to modify them myself. I have a 66 Baracuda and had a set of D453 Doug's, but the Idler arm would not clear them, and I did not want to dimple them up to bad, so I sold them.

You had the wrong Dougs. You need the D450.

http://www.jegs.com/i/Doug's+Headers/776/D450/10002/-1

the D453 fits the newer Valiant's and Darts.
1967-72 Valiant