Anyone run high-flow Cats to reduce hydrocarbon exhaust smell?
Then the cats are somehow removing the excess fuel, but unfortunately that does not mean your AFR reading is correct as explained.
I would be concerned that these are not going to last. That is the common outcome of fuel rich exhaust into a cat. They are not intended to remove excess fuel but to convert excess CO to CO2.
This has all been said before in this thread.
I understand and appreciate what you are saying, but by your own statements, it's pretty clear that you are unfamiliar with the Mopar ECM I am using. Each and every mis-fire the engine may have is recorded for each specific cylinder. This information is downloadable on a scanner. In over 2000 miles, there were less than a dozen mis-fires total. Also, Mopar doesn't use HEI. Their ignition is integrated into the ECM. HEI is actually a misleading term as it is the name of GM's electronic ignition. The motor is not mis-firing, and despite your beliefs to the contrary, the A/F ratios are very close to being spot on according to my plugs.
Speaking of reading plugs from engines running on modern gas, it is not hard to do if you know how. There is more to it than just looking for color after a few miles. I check mine after several hundred miles and they look as one would expect on a well tuned motor.
My other car has a six pack on it. I used the same wide band on it to jet the carbs. You got me thinking about what you had mentioned regarding O2 readings when there is excessive oxygen in the exhaust. That motor has even more duration and overlap than this one, and the O2 readings reflect exactly what you said. At idle, they go off the scale beyond 22-1 A/f ratio and beyond until the gauge blanks.out of range. Just off idle, it clears up and goes back to reading accurately. The plugs on that motor are ideal looking as well.
The bottom line is that high duration, high overlap cams are designed to keep both valves open at the same time. This allows unburied fuel and air into the exhaust. No amount of tuning is going to change that. High flow cats are an inexpensive solution to having to live with the odor that results from running high overlap cams. Why don't I just put a smaller cam with a wider LSA? Because I like performance. This little 408" motor pulled my 3700lbs car to a win in front of a Hellcat in the quarter mile. It will probably do it again this year at Track Day for Spring Fling, but will smell a lot better on the road between then and now.