[T2] Carbs and change if altitude

[MUTS .]

I agree with the advancing of timing, but always wondered why gas bought 
at altitude has less octane, which at increased levels (premium gas) is 
supposed to lessen chance of pinging?  I realize that the same volume of 
air sucked in will have less O2, so you will run rich and pinging on 
advance is less likely.

MUTS  = Michael's Ultimate Thumb Saver oboe support
93 Chevy Roadtrek 210P
78 VW Westfalia Camper