Bought a bench belt sander to true up the flanges on the headers. RYobi was $148 at Home Depot, every other sander costs more for some reason. 80 grit worked extremely well. Didn’t have to take off too much material. Both flanges are flat. Used 2 different levels and a flat MDF board to check. Won’t have exhaust leaks plus I’ll be using MAHLE multi steel gaskets.

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