is the new line a Mack line or aftermarket? You may get lucky by pulling the line and using a 400 grit or higher emory cloth and buff the ball ends to get the groove out. I do it on E-Techs with sucess.. I pinch the emory cloth between my thumb and pointer finger, and rotate the line back and forth.. it doesnt require a lot of buffing, i just do it till the groove is gone or nearly gone. If you have another injector, check to see if the spacer tube thingy on the end of the line is not touching the injector. you can do that in your hand. I remember years ago, the ball on the end of the line was small, and that tube thingy would nearly touch the injector, which when torqued down it will not have the correct pressure to seal the ball into the injector port.. I have taken the line to the bench grinder and put a chamfer on the tube thingy to make sure it would not press against the injetor. I hope I typed this in a way that is easy to understand... Jojo