Quesions re: AFR readings

[hughc]

I installed an AFR gauge on my '83 sc about a year ago. The gauge reading has always varied between 14.4 to 15.2 and I assumed it was normal. At full throttle the reading is 12.5 which I also assume is correct.
This past winter I replaced my sc muffler with a Borla, the catalyctic converter was replaced quite while ago with a cheater pipe.
Today after a 100 mi drive I noticed the exhaust outlet was very sooty. Too sooty in my opinion. Given the AFR readings that I have, is a sooty exhaust pipe normal?
If that situation isn't normal, can I tweak the fuel distributor slightly to give a somewhat leaner mixture? If so, what direction do I turn the adjustment screw to lean out the mixture.
Thx
hughc

[cabmandone]

I'd trust the gauge and wouldn't mess with it. If you're running in the 14.4-15.2 range at speed and 12's at WOT it seems to me like it's running pretty well. I'd look at the plugs before I'd look at my exhaust tip as an indicator and yes mine has some black soot but so does my 2012 F250.

[hughc]

I checked the plugs and they are very clean, light gray even so I think that's good.
The car runs quite nicely so maybe I should leave well enough alone.
Thank you for your reply Nick.

[Alan L]

Given the info so far I would go with the gauge data.
And the idle mix screw wont fix any AFR issue - except at idle.
Alan

[SkiVT]

My AFR gauge recommends performing the calibration steps yearly or after xxxxxx miles. That might be one other thing to confirm to be sure the numbers are as accurate as possible.