Just fiinishing up a frame off restoration on a 67 GTO HO. Got it running today, but the only way I could get it running was a jumper wire from the + side of the battery to the + side of the coil. I had no spark to the plugs prior. With the key on I got 12 volts on both sides of the coil. When I turn the Ign. switch to start the engine, it turns over however I no longer have volts coming out of the neg. side of the the coil. I did put a new engine harness in and a new high toqure starter. Any help as to what I can do to fix this.