1. Disassemble the Engine:
- Remove the intake manifold, cylinder heads, and oil pan to access the internal parts of the engine.
2. Inspect and Measure Components:
- Carefully examine the pistons, cylinders, crankshaft, and camshaft for wear or damage.
- Measure the cylinder bores to determine if they need boring or honing.
3. Block Preparation:
- If cylinder boring is required, have the block machined to ensure proper piston-to-cylinder wall clearance.
- Deck the block surface to create a flat and even surface for the cylinder heads.
4. Pistons and Rings:
- Select forged or hypereutectic pistons that are suitable for high-performance applications.
- Choose the appropriate piston ring set to ensure proper sealing.
5. Crankshaft and Connecting Rods:
- Inspect the crankshaft for any signs of wear or damage and have it machined if necessary.
- Use forged steel connecting rods or upgrade to stronger versions for improved durability.
6. Camshaft and Lifters:
- Choose a camshaft with a profile designed for performance applications.
- Install new lifters and pushrods to match the camshaft specifications.
7. Cylinder Head Modifications:
- Perform porting and polishing to improve airflow into and out of the combustion chambers.
- Install larger valves with a multi-angle valve job to optimize airflow.
8. Intake Manifold and Carburetor:
- Replace the stock intake manifold with a performance-oriented version that has better flow characteristics.
- Upgrade to a larger carburetor or throttle body to increase airflow.
9. Headers and Exhaust:
- Install long-tube headers to improve exhaust flow and reduce backpressure.
- Use a performance exhaust system with a free-flowing muffler.
10. Ignition System:
- Install a high-performance ignition system, including a new distributor, spark plug wires, and spark plugs.
- Consider upgrading to an electronic ignition system for improved reliability.
11. Fuel System:
- Upgrade the fuel system with a higher-capacity fuel pump and larger fuel lines to ensure adequate fuel supply.
12. Tuning:
- Once the engine is reassembled, have the carburetor or fuel injection system tuned by a professional to optimize performance.
It's important to note that achieving 300 horsepower from a 1969 Chevy 350 may require additional modifications and upgrades beyond the ones listed here. The exact combination of parts and adjustments will depend on your specific goals and budget. Consulting with experienced engine builders or performance shops is recommended to ensure the best results.
