You talking about these guys?
https://www.14point7.com/pages/products
I'd forgotten all about them! While the AEM has gone up in price since I got mine, it is running the newer 4.9 sensor.
https://www.amazon.com/AEM-30-4110-U.../dp/B00N3VGPYS
I also have an older Tech Edge in the dually, but I blew my wad on that because the standalone I was running at the time didn't have any sort of datalogging capabilities. The wideband does though.
1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
2004 Corvette Z06 with longtubes.
Several points:
I agree on swapping PCM to part # 0411 and running OS 12212156 (with matching trans segment).
For street usage, experienced tuner will run WOT at around AFR 12.6 which will be safe for the motor. I agree that a novice tuner should run WOT AFR 12.2-12.3 since this gives a greater error margin (err on the side away from distaster).
The WOT AFR 13.0-13.2 that you see mentioned in various places is only set by running on dyno and observing power increasing (slightly) as rpm continues increasing above where peak torque occurs, and is done only when spark knock is absent. This is done very carefully on the dyno. (Note that peak torque is a special point, this determines how to set WOT fuel/air and spark advance).
With mods being LS6 intake and LT headers you can probably run the stock 2002 F-car 12212156 tune and see how it runs (using a wideband).
You're right, it was a seasoned Dyno tuner that said they like 13:1.
1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
2004 Corvette Z06 with longtubes.