RodsRideSS

I feel compelled to post this most unusual but serious problem with the timing on my SS. I put a new distributor in my highly modified 305, and the thing would not run properly. I maintained all electronic controls, ECM, CCC, Q-jet, Electronic EGR, TCC...etc.
Here's the problem...
It would start fine, warmup was normal, idle decent with 15" vac(217-224 duration @.050). When I would take it for a run, it would suddenly start popping and banging @ light throttle(high vac and most timing advance) and would only run with my foot in the gas. Sometimes I could ride the brake with my foot in it, and the problem would go away!! I discovered that it stared to do it after the ECM took over the timing...in the garage or on the highway.
Here's what I discovered:
It would run OK if I unplugged one of the sensors...check engine light would be on and the timing would run off the module instead of the ECM with minimal advance. So....It seemed to screw up when in advance mode.
I removed the dist cap and inside was totally destroyed...burnt, melted and the coil post almost fell off...the thing was running like this!!! I started thinking that The timing must be jumping to the next post or crossfire or something.
The Fix: I bought a new cap'n'rotor, cut an opening in it; lined up with the #1 post and put it all back together. With the engine running, point your timing light in the opening and look at the phase of the rotor to the post.
It should be right on..but mine was off by 33deg !! the spark was jumping about an inch to the post!!!
To make a long story short...I removed the dist, and found the reluctor did not line up with the magnetic pickup (with the rotor pointed at #1 post). Had to do a little homemade machining....slotted the holes for the magpickup and lined everything up...everything is great!!!