Well, I am a little boring I guess. I have made stupid mistakes but no near misses. The last big block a friend and I built back in the racing days was my last big blunder. I put a lot of money into this motor, all the best of everything. Short block was together, got the heads back, and being in a hurry, my buddy set the heads on and started bolting them down. I came along and torque them. When we finally got around to putting the new aluminum intake on, it would not fit. I had the machine shop deck the block, and thought, what did they do. So, after scratching our heads and making a few phone calls, the machine shop decked the block, but did not put the alignment tubes back onto the block and my buddy just set the heads on thinking the bolts would align the heads with the block...Now, sounds simple, but the car set for two weeks while I and the machine shop went back and forth.. It took me a long time to finally set foot in their door again....