#2 If the timing mark is that far off, the outer ring of the harmonic balancer has slipped.
#3 That's to say you don't see the timing mark move when using the timing light. Put a hand vacuum pump on the advance can and see if will hold a vacuum or advance the timing when the engine idles. No vacuum pump, just suck on the end of the hose
#4 Check the voltage there, with the engine running. If that 6V is while running, you may have a partially shorted primary winding in the ignition coil. Primary coil resistance should be around .3 ohms to .5 ohms. Even if you still have a ballast resisteror, it will only drop 2V from the 14V charging voltage leaving you with 12V running. You didn't say if it is HEI or aftermarket.
