I was expecting 2 nice flat and smooth block-off plates but instead got a pair of pretty rough surface stampings. Thes ARE NOT flat as one would expect had they been made by CNC process. The thick-ass gasket included in the kit can compensate for the lack of flatness of the plates. I flatened them myself over a wet piece of 220 paper over a glass surface. Probably not necessary but I wanted to make sure I never have to mess with those pesky inverted bolts under the plenum.