Changing one OS to a Flex Fuel OS with both OS from same year, same P01

[rel3rd]

Right now, I am running straight E85 on my 2000 Trans Am.
Mild 6.0, 4L80E, dual 255 pumps, 60# injectors

All I did was change the Stoichiometric setting from 14.62xxx, to 9.68, and it is running (good and) real close to Lambda at cruise, but like .650 or so when in PE (pegged rich on my AEM wideband gauge). I have done ZERO tuning to it yet, as I just pumped the flex fuel in 2 days ago...

Before I acquired it, the car was P01 OS swapped to a 2002 Silverado, 3 bar, speed density, (RTT) setup.
Turbo is long gone, never to return...and not worried about VIN match or any of that.

I have unlimited 2002 Silverado/Sierra 4.8, 5.3, 6.0, 8.1 tuning license
I found a 2002 Silverado based tune in the HPTuners Repository, already equipped with a Flex Fuel capability.

Can I just spend some time transferring all of my current personal tune settings into the Flex tune, then simply do a Write Entire, using the Flex Fuel enabled tune, to my existing PCM?


I'm not concerned about the FLEX tune still being an SD - 2 bar OS. If that's the only negative, I'm perfectly OK with that. I know I can run MAF with either, as I am doing it now.

I know I need to get the actual sensor, pigtail, etc., and run a wire to PIN 56.
If I am able to do this simple OverWrite, the whole E85 conversion will cost under a hundred bucks...

Pics FF1 and FF2 are the FLEX FUEL Tune calibration details, and FF3 and FF4 are my current calibration details. I also attached a copy of both tunes....

[rel3rd]

Would it be feasible and/or EASIER to return (WRITE ENTIRE) the PCM back to a STOCK 2002 Silverado 6.0 OS first...then go to the 2002 Silverado FLEX FUEL 2 BAR OS setup?

I do NOT have the STOCK file for this car...