I agree, check for grounding. Also, I would agree that you should swap out the ignition to be sure that's not it. Has the harness to the ignition been modified? I put in a kill switch, perhaps you have had your harness jumped and rewired poorly. Is the engine grounded in 2 places and then I think there is a frame to body ground. Your battery is grounded to the fender and the RH head?
One other thing to try is unplug the headlights and leave switch on.. Ie. Is it coming back from bulbs or just switch.
All wires to the coil are in good shape and connected properly?
Engine Test Stand Playlist: https://www.youtube.com/playlist?list=PLwoxyUwptUcdqEb-o2ArqyiUaHW0G_C88 restoring my 1968 Firebird 400 HO convertible (Firedawg) 1965 Pontiac Catalina Safari Wagon 389 TriPower (Catwagon) 1999 JD AWS LX Lawn tractor 17hp (my daily driver) 2006 Sequoia 2017 Murano (wife's car) 202? Electric car 203? 68 Firebird /w electric engine 2007 Bayliner 175 runabout /w 3.0L Mercuiser__________________________________________________________
