Tier 1: Relatively Inexpensive, Decent Gains
* Air Intake: Replacing the restrictive factory air cleaner and intake with a high-flow system (e.g., K&N, Spectre) significantly improves airflow. This is usually a cost-effective first mod.
* Exhaust System: A free-flowing exhaust system (headers, cat-back, or full system) reduces back pressure, allowing the engine to breathe easier. This offers a noticeable power increase across the RPM range. Long-tube headers typically yield the largest gains but might require other modifications (like O2 sensor relocation).
* Ignition Upgrade: A performance ignition system (e.g., MSD, Mallory) provides a stronger, more consistent spark, leading to improved combustion efficiency and power.
Tier 2: Moderate Cost, Significant Gains
* Cam Swap: A performance camshaft tailored to your engine's specifications (compression ratio, intended use) is a major power adder. This requires more mechanical knowledge and potentially other related upgrades (e.g., valve springs, pushrods). Choosing the right cam is crucial, and an incorrect choice can negatively impact performance.
* Carburetor Upgrade (if applicable): If you have a carburetor, upgrading to a performance carburetor (e.g., Holley, Edelbrock) with appropriate jetting and calibration can significantly improve fuel delivery and power.
* Computer Tuning (if applicable): If you have a fuel-injected 350, professional tuning (via a handheld tuner or dyno tuning) will optimize the air/fuel mixture and ignition timing for the modifications you've made. This is extremely important to maximize power and prevent engine damage.
Tier 3: Higher Cost, Substantial Gains
* Cylinder Heads: High-performance cylinder heads (e.g., Edelbrock, AFR, Dart) offer improved airflow and combustion efficiency, resulting in significant horsepower gains. This is a more involved upgrade requiring machining and potentially other engine work.
* Intake Manifold: A high-rise or performance intake manifold will improve airflow to the cylinders, complementing upgraded cylinder heads and carburetor/fuel injection system.
Important Considerations:
* Compression Ratio: The compression ratio of your 350 significantly impacts the effectiveness of certain upgrades. Higher compression generally requires higher-octane fuel and careful camshaft selection.
* Professional Installation: While some modifications are DIY-friendly, others (like camshaft swaps and cylinder head installations) are best left to experienced mechanics.
* Complementary Modifications: For optimal results, consider upgrading components that work together. For example, a high-performance camshaft is less effective without a corresponding intake and exhaust system upgrade.
In short: Start with the Tier 1 mods (intake and exhaust). Then, depending on your goals and budget, progress to Tier 2 and potentially Tier 3. Always research thoroughly before making modifications, and consider consulting with experienced engine builders for guidance. Don't forget about proper tuning to ensure your engine runs safely and efficiently.
