Todays gas basicly sucks anymore but like said above Sta-Bil and make sure you store it in a metal container, the plastic containers bought at all the stores allow allot of the ingrediants to escape with the fumes? I know what I'm trying to say but its not comming out right. I picked up a coupla 55 gallon drums from a distributor who sold race gas which is what it comes in. Another thought also is to blend it 50/50 with AV gas as that will bring the octane up as well as it has additives to stop gelling and vapor lock, those 2 issues can be bad at 1000+ feet
We have stored gas for long periods that way, although my neighbor bought a 300 gallon tank and slowly filled it he burried it down a bit and set it up right works great he also adds Sta-Bil as he fills it.
Good Luck!