I purchased a set of D453's for my 69 340 4 speed car. They don't work with the 4 speed as the bell housing side of the z-bar is impeded by one of the header tubes. Can't get the clutch hooked up without some modification. I can say that Doug's sent special reference to the 727 tranny saying that an ome Chrysler (Mitsubushi) mini started is recommended (translate: required) for the 727. I attempted to use another (chubbier) mini and was not successful. Spent hours on the phone with Doug's tech suppt to no avail. They insist that the headers fit, they don't fit with the 4 speed application. I'm stuck with an expensive set of headers I can't use. As the Dart is an original matching numbers car I'm unwilling to modify the z-bar or go to a hydraulic clutch so the headers are out. I'm thinking you may have better luck with the 727 so long as you go with the recommended mini starter.