2003 Tundra 4.7 4x4
I put a straight edge to the mounting side of the headers and they were not even close to being straight. I had to work on them with a file and a straight edge for a couple of hours before they were perfect. Install was not easy, but I have no leaks, slight power gain and slight sound improvement. I have intake and exhaust as well. These headers made more noticeable power gains than the intake or exhaust individually.