[Fasterthanyou]

Originally Posted by JL8Jeff

Carbon buildup is the result of incomplete fuel/air combustion partly due to a weak spark/flame situation. Using a longer/hotter spark will allow complete combustion of existing air/fuel and will also promote burning off the buildup. Stock ignition systems are pathetically weak. Manufacturers don't run high energy ignitions due to warranty/longevity concerns. I ran the JAcobs Omni-Pak on one of my old 69 Camaros with a POS 307 motor. I finally decided to do a cam/head upgrade for more power and when I pulled the heads off, the heads and pistons were incredibly clean. I did a head swap on the Yamaha 650 jetski motor in my boat and I had been running the MSD coil/wires on it and the head and pistons were spotless and that's a 2 stroke with oil/gas premix. And I saw the deposits burning off on my SS454 right after I put the distributor and Hypertech coil on it. The exhaust had some smoke coming out for about 10 miles of driving. It has never smoked since then, but it's a low mileage motor so it couldn't have had too bad of deposit buildup. If you're getting any kind of pinging from the motor, then you probably have some buildup in the combustion chamber or on the valves.

I'd agree with you that in 69 the ignition setups were pathetically weak. Once emissions was a concern ignition systems from OEM have stepped up rather nicely. The CNP on today's gen 3 chevy motors are excelent setups that will surpass any CDI or DIS (wasted spark) setups that aftermarket companies are still offering. The stock GM HEI setups of the 80's are awesome setups in there own right. The only problem with them is there single coil secondary voltage troubles at high engine speeds. Everything else is rather excelent.
I also disagree that a complete burn decreases build-up. Build-up of deposits in the combustion chamber are the result of completely burned mixtures. The buildup that's left behind is formed from complete combustion of all the impurities in the gas, oil, and air. Dyno juice from the PCV and ring blow-by is the main source of build-up. No amount of ignition upgrading will chean the chambers and if anything it'll promote the burning of ALL impurities creating more build-up.
A clean chamber has everything to do with your oil, ring condition, PCV, and detergents in the gas you burn.