I did when I installed mine. I ported both sides, I guess you could call it porting. Really I just cleaned it up and belled the opening, I couldn't tell you if if really helps, bit I figured I would do it while I have everything out and apart. I did take a good bit of material out because the casting is pretty rough. I would think that opening it up that much and cleaning everything up would help something.
Ok fellas, I ported the hell out of my Duttweiler neck today. Cut a tremendous amount of metal out of the thing. I port matched it to the size of the throttle body. I also did the same to the outlet side of the intercooler as well. Also made a new uppipe from a true 2.5" mandrel bent elbow. Unreal how much difference it made. It moves so much more air that I am going to have to add some fuel with the chip as it is slightly lean. It will spin the tires now at 30-35 mph at only 17 psi. I can't wait to get some slicks on this car and see what it can do at the drag strip.
