Hy LandonL, As tiny said a thread "chaser" or cleaner is a better choice to clean threads in the block than a tap, you don't actually want to remove any metal, just clean the threads that already exist. The wire brush is a better tool than a die to clean external threads, again you don't actually want to remove any metal.Something a lot of people have never heard of is class of fit, fasteners for different applications have a different class of fit, for example wheel studs and nuts, if they are in good shape they should be snug to install right from the first thread, that is because they have more stringent specifications for fit between the two pieces. Replacing head bolts is a fairly modern practise, all the engines from I believe the 70s and older routinely reused their head bolts. For the old Chevy/GMC engines, I believe there were two different strengths of bolts used, they had different head markings to identify the different bolts
