just some info...

higher octane fuel doesn't burn slower, nor does a slower burn prevent explosion. actually what happens in the cylinder is called deflagration. the higher the octane, the more a fuel/air mixture can be compressed before it ignites (pressure+friction=heat). all engines have a compression ratio. I think our trucks are like 9.1:1 or something (dont have the manual handy but it's in there). Lower octane fuel will ignite at a lower pressure than higher octane fuel. That's why if you get a knocking in your engine, they suggest switching to higher octane fuel - the knocking is the combustion of the fuel/air mixture due solely to pressure, instead of combusting due to the firing spark plug. this is also why higher performance engines require higher octane fuel - the engines have higher compression ratios, so they need fuel that won't combust until it's supposed to.

just some food for thought. http://www.howstuffworks.com is a gold mine!