1. Internal Engine Work (Essential):
* Increased Compression Ratio: A higher compression ratio is fundamental for increased power. This typically requires replacing the pistons with high-compression units, potentially needing head work to achieve the desired compression (likely 10:1 or higher for this power goal). You'll need to carefully select pistons to match your chosen crankshaft and connecting rods.
* Crankshaft and Connecting Rods: Stock components might not be strong enough to handle the increased power and stress. Forged steel crankshaft and connecting rods are highly recommended.
* Camshaft: A performance camshaft with significantly more aggressive duration and lift is needed. The camshaft profile will need to be carefully selected to match the cylinder heads, compression ratio, and intended RPM range. This will impact idle quality, making a higher-stall torque converter essential.
* Cylinder Heads: Stock 283 heads are restrictive. Aftermarket performance heads (e.g., aftermarket aluminum heads) with larger valves, improved flow, and better combustion chamber design are crucial for reaching 315 hp. Porting and polishing the heads would further enhance airflow.
* Valvetrain: High-performance valve springs, retainers, and pushrods are necessary to control the valves at higher RPMs with the more aggressive cam. Roller rockers are also a beneficial upgrade.
2. External Modifications (Important):
* Intake Manifold: A high-flow aftermarket intake manifold is vital to supply the engine with sufficient air. A dual-plane intake is a good compromise between low-end torque and high-end power.
* Carburetor: A larger, high-performance carburetor (e.g., a 600-750 CFM Holley or similar) is needed to match the increased airflow. Proper carburetor tuning is critical.
* Exhaust System: Headers with a free-flowing exhaust system (larger diameter pipes and appropriate mufflers) are essential to efficiently expel exhaust gases. The exhaust system design significantly impacts power output.
* Ignition System: An upgraded ignition system (e.g., a performance distributor, coil, and wires) will provide a stronger, more consistent spark for improved combustion.
3. Other Considerations:
* Machine Work: Precision machining is required for many of these components to ensure proper clearances and tolerances. This work should be done by a qualified engine builder.
* Balancing: The crankshaft, connecting rods, and pistons should be dynamically balanced to reduce vibration and stress on the engine.
* Fuel System: The fuel pump and fuel lines need to be capable of delivering the necessary fuel volume at higher engine speeds.
* Cooling System: An upgraded radiator and cooling fan may be necessary to keep the engine from overheating under heavy load.
* Lubrication: High-performance engine oil and a high-volume oil pump are recommended to ensure adequate lubrication.
In summary: Achieving 315 horsepower from a 283 requires a significant investment in parts and professional engine building services. It's not a simple bolt-on project; it's a substantial engine rebuild. The cost could easily reach several thousand dollars, depending on the quality of components used and the labor involved. It's advisable to consult with experienced engine builders to plan and execute this project properly. They can help you select appropriate parts and ensure the build is done correctly for reliability and the desired horsepower output.
