I just replaced the coil when I put in my Crane ignition. My original coil was old and sickly and would cause the engine to bog and waver at wide open throttle. I put the Crane electronic module over the hole in the firewall left by the missing original coil, and a big Mallory coil on the left fender liner. Cured the WOT surging.

With the points gone the timing marks are rock steady under a timing light. Before they would jump around up to 5 degrees.