What I mean is you could not order a 440 Dart in 1968 from the factory. Mr Norm did the GSS Darts on his own. You could order a Superbird in 1970 because it was sold through the factory same as the 69 Dart 440. Dont matter where it was done as long as you could get it from the factory and not be a dealer installed eng done by that dealer. I wish they were legal but I am not sure they are.
I also agree they would not run at the top with the exh manifolds they use and the little carb and crappy intake. I have seen a 6pk car run in the 10.80's and a Max Wedge run 10.30's and of course the Hemi at 9.90's with the Ford in the 9.80's. Ron