* Engine modifications: Has the engine been modified (cam, intake, exhaust, etc.)? Modifications significantly impact ideal timing.
* Fuel type: The type of fuel (regular, premium, etc.) will affect the ideal timing.
* Engine condition: Worn parts can affect timing requirements.
* Altitude: Higher altitudes require different timing.
Therefore, you MUST consult your owner's manual or a reliable Chevrolet service manual specific to your year and model. This manual will give you the *base* timing specification for your engine, usually expressed as degrees before top dead center (BTDC). This is usually a starting point, and often requires further fine-tuning using a timing light and dwell meter.
Improper timing can cause:
* Reduced fuel economy
* Reduced power
* Engine overheating
* Engine damage
Do not attempt to adjust timing without the proper tools, knowledge, and safety precautions. If you are not comfortable performing this task yourself, take your truck to a qualified mechanic.
