My 69 is acting funny lately. It has started to backfire through the exhaust. I have a 383. Initial timing is at 6 degrees with the vacuum advance unhooked I am at 25..I hook up the vacuum advance it goes to 45!! This has just started. I also seem to have a real weak spark (Complete msd ignition. The coil is a blaster 2). Also..the car seems to be shocking me when I get out?? I am thinking a bad ground for the shocking me and maybe a bad coil starting to develop, but why would the vacuum advance change so much? The backfire out of the exhaust? What could cause this? The car has also giving me trouble before not wanting to start...usually at a inopertune time and there would be no spark, but It would be ok after awhile. Do I need to buy a new coil and change the advance springs inside my distributor?
69 x-11..LS1, 420.88 horse to the tires,750 Holley Ultra DP, Torquer V2, darksides headers, PRC heads, 10.8:1 compression, forged bottom end, 5 speed. 2008 King Ranch F150 4x4.