Kyle97GMC
NO SIR IT'S NOT A CHEVY.
I have a Black Bear tune and it is set for 91 octane. I have ran it in every tank except for when I was hunting and all they had in the mountain town I stopped in was 87. I filled it up with fifteen gallons and other than feeling a little sluggish that tank I have had zero problems. I'm sure just finishing that tank won't cause any harm to it especially if you put an octane booster in there