A homemade coil tester you might be interested in. Used a old phonograph motor with a hex nut attached to the shaft operating the points on a 60s GMC distributor plate. Has an on-board coil and cond for testing plugs. Jumpers to connect to the unknown coil. Can run a coil for a few minutes, hours, days or weeks, if you like. If the OBM has exposed kill connection(s), using longer jumpers the coils can be tested in place without pulling the flywheel. Adjustable DC input. Can add heat with a hair drier to stress the insulation. Works for me. 😉
