11.6 afr? You say the car runs great, so, the first thing I would look at is the gauge/sensor itself. It's Aftermarket, so right off the bat I don't put any faith in it.

Is it a brand-new gauge or was it used on another car you race? Is the sensor clean? Clean it with oven cleaner and put it back in, re-try it. If it's a generic Bosch or Denso order a new one and try it. Sensor positioning is highly important: Is the O2 sensor at the correct length from the head?

I had an O2 sensor go bad on a high performance application that would still run great at WFO but there's no "check engine" light for it: similar to your aftermarket gauge. The only way I figured what the problem was when soot started to show up in the pipes. 12.5:1 compression, so I run my own fuel mix with Lead in it, so, it ruined the O2 sensor. What do your exhaust tips look like? You run race gas in your 392?

I know this is a race forum, but what is happening with your fuel mileage in normal driving of your car? Did it take a dump? If not, and everything is otherwise normal I'd say the gauge is the issue.

Check the little things first before re-engineering the whole car.

Finally, from an Engineering/Warranty standpoint: Dodge put millions of miles on that engine pre-production and if 11.6 at WFO is what's needed to protect it from burning up, that's what it needs. Don't mess with it. Tuner names mentioned here, (and I really like the "what happens if I push this button" reference ) have blown up plenty of Hemis. Especially "Hemi fever", Google him on the Ram Forums between 2004 and 2010 and see what comes up.