[Michael C Henry]

I also have a 427 SO with dual inline Holley 600 CFM carbs. My side pipe exhaust are all sooted up also. I just had new primary metering blocks prepared with replaceable idle restricters. The new primary metering blocks came with .026" idle fuel restricters and #5 powervalves ( I had #6 powervalves before). I changed the idle restricters in the Quick Fuel Technology secondary metering plates from .038" to .032". The problem I had was mostly the Idle was way to rich. Startup in the garage is a mess . With all the soot in the pipes and the engine creating water (initialy in liquid form), I have black spatter blubering out of the ends and joints. I have single car garage so correct placement of cardboard is a great help. It appears to be running better and I hope the side pipes will clean out over time. In reality, the secondaries are influencing the idle but probabably have never opened. If you read the thread on this forum "inline dual fours" you will see some detail. I'm still running #65 primary and #67 secondary jetting. The move downward on the powervalves helped the surging under a light load at near idle (second gear in a hospital parking garage). Recent state emission testing, cruise HC was over limit but close. Idle HC was over 10 times the 220 PPM HC limit. I'm hopping that most of the sooting was from the idleing. It is a work in progress.