a72z4me

Hi Guys,first time posting here on this site.I have a firing issue with my car(I think).It's a 72 240 with L28 bored 1mm,E88 head from 260,dual weber DGV's,82 dizzy with MSD6 ignition,ZX alternator.I've tried adjusting the timing from one extreme to next,checked plugs,wires,dizzy with it still misfiring.The alternator is new along with the MSD,although problem existed before these items.The alt is also drawing to the over charging side of the gauge.Could there be a short to ground somewhere causing this problem(the overcharging existed with the 240 alt. as well)Any suggestions greatly appreciated.