Ok lets say you have a 71 Dart with a 440 and eddy aluminum heads. Who makes under chassis headers? and how big can you get them in. 1 3/4, 1 7/8, 2.0 ect. and if you can get them in 1 7/8 or bigger how hard is it to each the plugs? and what would be the cost on some of these headers? Has anyone here ever worked with a set of under chassis headers in a 70-72 440 Dart be for?