Could somebody explain these two concepts to me? Why do different octanes allow you to run different advance and compression?

------------------
1989 Pontiac Firebird Formula LO3 Auto
-180 degree stat
-Hooker Cat-Back
*****Possible summer '01 mods*****
Open Element, Auburn Posi, Keyless Entry, wonder Bar off the IROC, 4th gen seats, T/A tail lights

1985 Camaro IROC-Z LB9 Auto
http://www.geocities.com/krt80/

Raising octane levels in gasoline makes it less volital. What that means is it lets the fuel burn, and not explode. You don't want the fuel to explode, you want a burn, a complete burn. By increasing timing, you start the burn earlier. That means the burn starts even more before top dead center. Then, as the piston comes up to TDC, the temp. increases because the pressure increases. The more presure, the more heat, the less of a burn and more of an explosion.

In short, you increase the chance of detonation with higher compression and lower octane.

------------------
'82 Firebird, dead stock, 9 bolt disc rear, over 200,000 miles and still going strong, more to come...
http://www.spinfrenzy.com/stingerssx...easures.html#4

Oh ok, I had some of that worked out in my head but now I understand. The way I had it worked out I figured that higher octanes didn't burn as fast, but that didn't seem logical to me then.

That's true, higher octanes burn slower. That's what alows you to raise compression, and advance timing. The slower it burns, the more stuff you can do.