Chevy HEI Distributor problems

[vettestr]

Here are a few items to check as they are the know faults or componets that can fail. Check rotor for black line on bottom of rotor in the center for carbon tracking or blow through, replace if needed also check cap for same as crossfire from jumping to wrong cyl can happen. The green wire from the module that goes to the moving plate can have wire insulation failure from moving with vac advance all the time and become a short. Have module checked at chain parts store like Checker for failure with RPM and coat with generous amont of white heat paste between module and dist. body or unit will fail in short time. Even a bad plug wire will misfire with load or RPM so if a little crazy run your hands along length to see if you get shocked ( can look at wires and move around in dark for sparks if not up to 40KV shock!!! Pull any plug wire and put a plug in wire and place in area you can watch end od plug. Start engine and look at plug to see if spark is neon blue, a yellow orange color means bad coil as a rule MUST BE NEON BLUE SPARK. Do not put plug test on polished valve cover as it will leave a mark !!!. If damper is wrong just time by ear and then check to see if in expected range. If needed can explain how to check with a dial indicator on # 6 cyl. but long thread needed to explain.
If I had to guess 1 or 2 even bet=it is a bad plug wire from header burn 2. bad cap/rotor 3. green wire to advance plate 4. module is on or off as norm but electronics can be wierd to trace. If happening for a while you could have fouled a plug and now have 2 problems to mask eack other. All this ASSUMES NO computer in car that can be a whole new deal.