the red lead needs to go to the side of the coil that the points wire connects to which is neg.the bigger the gap the smaller the dwell reading. If the dwell changes when eng.rpm is increased the dist.has worn bushings.Dwell is the amount of time the points are closed vs the amount of time there open.the more dwell the longer the coil has to charge up giving a hotter spark that's why the came out with duel point dist.it gives a longer dwell time.