In the book all they list is 3" in / 3" out 10.25 length.. I dont have a Y pipe here to measure but I have a magnaflow 3" x-pipe. The outlets ar 6" center to center; outside to outside on the outlets is 9".. overall width is 9.75". The Y pipe looks smaller in the book.. I have a y pipe is a ripoff of a magnaflow, which is 4.5" center to center 7.25" outside to outside, 7.75" overall width.. 8.75" long. The magnaflow should be pretty close to this one.