What octane fuel grade should you put in your 5.7 liter firebird?

The recommended octane rating for a 5.7 liter Firebird depends on the year and specific engine. The owner's manual is the definitive source. However, generally speaking, most 5.7L Firebirds (especially those with the LS1 or similar engines) will perform best and be most reliable on 91 octane or higher. Using lower octane fuel *might* not cause immediate damage, but it can lead to pinging (knocking), reduced performance, and potentially long-term engine problems. Always check your owner's manual to be certain.