Here's a breakdown to help you decide:
* Stock Throttle Body: The stock 58mm throttle body is generally adequate for many naturally aspirated Z28s, especially if you're not making significant power modifications. Replacing it offers minimal gains without other supporting mods.
* Larger Throttle Bodies (e.g., 65mm, 70mm, 75mm): These are popular upgrades, but only beneficial if you have other modifications that increase airflow, such as:
* Performance Air Intake: A high-flow intake system is crucial to supply the increased airflow a larger throttle body allows.
* Headers and Exhaust: A free-flowing exhaust system is needed to expel the extra exhaust gases.
* Performance Camshaft: A camshaft with more aggressive lift and duration will improve airflow, maximizing the benefits of a larger throttle body.
* Tuner: A professional tune is absolutely essential when using a larger throttle body. Improper tuning can lead to poor drivability, reduced performance, or even engine damage.
Without these supporting modifications, a larger throttle body will likely offer little to no performance improvement and may even negatively impact throttle response and drivability.
Brands to Consider (if upgrading): Several reputable brands offer throttle bodies, including but not limited to:
* FAST (Fuel Air Spark Technology): Known for high-quality throttle bodies.
* Holley: Offers various throttle body options for various applications.
* Edelbrock: Another reputable brand with a range of throttle bodies.
Recommendation:
Before purchasing a larger throttle body, carefully assess your current modifications and future plans. If you're only adding a throttle body without addressing intake and exhaust restrictions, it's likely a waste of money. If you're already planning or have significant power modifications, then a larger throttle body *could* be beneficial, but only with proper tuning. Always prioritize professional tuning after installing a larger throttle body.
In short, start by defining your performance goals and the other modifications you have or plan to make. Then research specific throttle body options and consult with experienced tuners or mechanics familiar with LT1 engines to determine the best choice for your specific application.
