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Octane is a retardant. It's not a measure of how powerful the gas is. The purpose is to raise the temperature required to ignite the gas so it doesn't pre-ignite in high compression engines which can destroy the engine. Any "hotpoint" inside the combustion chamber, whether a tiny bit of carbon or even the end of the spark plug itself can ignite a compressed fuel mixture if the hotpoint is hot enough. If this happens before the spark plug actually fires, which causes the compressing mixture to explode before it's supposed to, then you hear "knocking" which is the jolting of the engine trying to push a piston up when a pre-ignited explosion is trying to push it down. Needless to say this is VERY BAD for the engine.

In order to avoid this problem retardant is added to the gas to raise the temperature required to ignite so only the spark plug is hot enough to ignite the gas. This is known as octane rating. The higher the compression ratio in an engine, the more octane needed to prevent pre-ignition. This is why racing gas is 103 octane; because their engines are compressing the mixture to such a high degree it's hyper critical that ONLY the spark plug can ignite the mixture.

Street engines don't need 103 octane because their compression ratios aren't high enough to need it. A high performance street engine is going to be anywhere from 10 to 12-to-one compression and will definitely benefit from 91 or 93 octane whichever is available to you. Both the V6 and V8 in the Camaro will benefit from premium gas. Especially if you've improved the intake and/or exhaust.

The reason why our cars CAN run 87 octane is because the computer retards the timing to compensate for the possibility the gas can ignite too early. In essence because the retardant isn't in the fuel, the computer retards the ignition timing instead to protect the engine. As you can guess this will reduce the performance and efficiency of the engine somewhat.

To get the best performance run premium in both the V6 and V8; you can run 87 in a pinch if you have to and have no choice but try and use at least 89 if you can. Keep in mind it will take at least 100 miles of driving for the computer to accumulate enough readings to start readjusting the timing back towards performance mode. The programming is written to be EXTREMELY conservative in favor of protecting the engine; which is a good thing.