Hi all. I'm in the middle of re-installing my cylinder head after a blown head gasket and a head refresh and have a question. After clearing the threads in two bolt holes, I've decided that the tap is too agressive and will revert to less violent ways to clear the rest of the threads . Have any of you actually used a M13 x 1.75 tap to clear these threads without problems? My machinest provided the tap so he thinks this is no problem but I'm skeptical . I don't do enough of these to know if I'm being overly nervous or am I going to pull these two bolts through the head when I get closer to 90 ft lbs. Anyone with some experience here? Thanks in advance, Paul