I've got a '47 Chev. Loadmaster, I can't get any spark. I've repalaced all the obvious "tune-up" parts (points, cond., cap, rotor, coil) and still nothing. I checked my voltage at the coil with ign. switch on, I have 7.5 volts, while cranking the engine over, I have 5.5 volts. Is my starter drawing too much current and not leaving enough for the ignition? (I did this test w/plugs removed to reduce compression and reduce strain on the starter)