[imagine2frolic]

Most likely many hardware stores will have the little plastic sheet with holes, and threads. Once you start figuring out what is what. You can place them in plastic drinking cups with sizes marked for future reference. By the time you are done with the car you will know a 8mm 1.5 from a 5/16 course just by glancing at it. If you are restoring the car? You might want to get a tap & die set. Both metric, and standard, and these are perfect guides to sizes. Sooner, or later you will need the tap & die set with all of the work ahead of you.