I bought this for the sole purpose of resurfacing and flattening my cylinder heads! I stuck some 150 grit on it with a very light mist coat of spray glue, flipped it upside down, and lapped my cylinder heads with it to get them flat, and then followed that up with 220 grit. They came out as flat as any machine shop could make them with a superior smooth and flat surface finish. It took me 2 hrs each to do them but man they came out nice. First go length wise, then cross wise, then at a 45 degree angle...rinse and repeat. My heads were only out by .0015" before I started, mainly where the head bolt pressure was. If your heads are terribly warped this probably won't work. I checked my heads using this surface plate upside down and some feeler guages, then a thin strip of foil and finally just marking up the surface with a sharpie and sanding it until the sharpie dissappeared. Saved a lot of money, and piece of mind that the heads are flat and didn't need to remove much material to get them there.