Just a quick note of thanks to all the search results on Black Sooty Plugs.
HEI;
Ignition Control Module. DONE. Should be in some type of trouble shooting thread. 350 SBC,Summit Dist and the ICM deteriorated slowly over a few days or so. Did a 600 mile road trip, no probs running 3000rpm/80mph, returned home and had idle issues after I filled the tank (Premium) as the engine stalled at a stop light @ 1mi from getting fuel. Did the normal stuff: Heet/seafoam for possible bad gas, carb cleaner, removed IMS, metering rods, cleaned and blew out with air. Ran ok above 1500rpm but would not idle. Pulled the plugs, black sooty and full of fuel, checked the float adjustment, in limits. I had a DUI ICM, swapped out the Summit and the engine runs like a dream. (also swapped caps to see if I had a coil problem before ICM swap) This was frustrating but got it figured out from our Forums. The ICM can partially and intermittently fail allowing the engine to start and run and other times not start at all.
Thanks
Roy

 

Might be good to have an ICM handy like a fuse, I'm ordering another shortly
@ $40-$80 depending on what HEI you have how much power you want.
Roy