Another 87 octane/aluminum heads question

Well that is true, but what DO you have to go by besides DCR? No computational method that I aware of accounts for VE.....so don't ignore the best tool available even if it is a best guess; it's been used for decades now, and folks have gotten a reasonable handle on how to apply the results. Without that, all you can do is experiment. The Wallace one allows you to look at 'effective' DCR that accounts for altitude.

I was wondering last night if your PCM looks just at a TPS or does it have an MP sensor? With your low density altitude, any MP sensor would read low all the time. I would assume the PCM would have a way to look at and figure out the static pressure and correct for that, but maybe not.