Iconic 427 runs very rich since new?

[lippy]

Understanding that my engine is different from yours (mine: 427 stroked to 487, solid roller, hotter cam, single plane intake, custom built Quick Fuel 850 race carb), I run my total advance at 36-37, use the black bushing to "retard" the idle timing, and use one light silver and one light blue spring. That seems to be the best combination for timing for my engine. I also use AR3924 racing plugs. I used to have carbon fouling problems but the car now seems to be dialed in better with smaller jets (72 primary, 84 secondary) and slightly larger high-speed air bleeds. Since mine is a solid roller, Brent advised me to idle it at 1100-1200 for proper lube, so it would run on at this speed. ERAChas suggested I let it idle high, put on the parking brake, put the car in second, hold the brake, and slowly let out the clutch until the engine speed gets dragged down somewhat. Simultaneously, I cut the ignition. It sounds difficult but it is really very simple and completely eliminates the run on.

[eedeutsch]

If your engine has a Pertronix distributor, that might be the problem. I replaced my Pertronix with a MSD 8350 Pro-Billet distributor. It did make a
big difference on the running of the car. It runs smoother and idles much better. Also it has increased the low end drive-ability and the overall performance.

[Cashburn]

Make sure you have the correct gear material on that new distributor. Losing that carb would go a long way too.