yea i have a 97 lt1 and i was wondering what is the highest or best fuel to run in it, gas prices are ridicoulous but i was just curious. thanks

 

If you read your Owner's Manual, it will tell you that the engine needs 91 octane, or it may suffer performance loss. IF the octane is too low, is may cause knock, and the PCM will retard the timing.

However, that requirement is based on sea level operation. As your elevation increases, the octane requirement drops. What it the elevation where you live?

The sure way to tell if you are getting knock retard is to run a scanner that can give you the knock retard readings. Drop the octane until you get knock retard..... and buy the octane level that does not cause knock retard. If you are willing to give up performance, the Manual indicates you can drop as low as 87.

 

^^^^Couldn't have said it any better than that^^^^