The Chevy small-block engine is a legendary powerplant, renowned for its durability, affordability, and tunability. But even a legend can benefit from a modern upgrade, and swapping in LS heads is a popular modification that delivers significant performance gains. This comprehensive guide delves into the details of this popular engine swap, exploring its benefits, challenges, and considerations.
Why Choose LS Heads for a Small Block?
LS heads, originating from the General Motors LS engine family, offer several compelling advantages over traditional small-block heads:
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Improved Flow: LS heads boast significantly improved intake and exhaust port flow compared to their small-block counterparts. This translates to increased airflow, leading to more power and torque throughout the RPM range. The enhanced flow characteristics are particularly noticeable at higher RPMs.
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Larger Valves: The larger valves found in LS heads further contribute to improved breathing, allowing for more efficient combustion and greater power output. This is a key factor in achieving substantial horsepower increases.
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Advanced Design: LS heads incorporate advanced design features, such as improved combustion chamber shape and optimized valve angles, leading to more efficient combustion and reduced emissions.
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Cost-Effectiveness: While not the cheapest upgrade, LS heads offer a compelling balance of performance gains and cost compared to other high-performance cylinder head options. The availability of used LS heads in the aftermarket can further reduce the overall cost.
Challenges and Considerations
While the benefits are significant, there are several challenges and considerations associated with this swap:
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Head Gasket Selection: Finding the correct head gasket is crucial. You'll need a head gasket specifically designed for the combination of an LS head and a small-block Chevy block. Improper gasket selection can lead to leaks and engine damage.
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Valve Train Compatibility: You may need to modify or replace components of your valve train, such as pushrods and rocker arms, to ensure proper geometry and valve clearance with the LS heads. This requires careful measurement and selection of components.
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Intake Manifold Compatibility: You'll need an intake manifold designed to work with LS heads and your specific application. This often requires custom fabrication or the use of an aftermarket manifold.
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Exhaust Manifold/Headers: Similarly, you may require custom exhaust manifolds or headers compatible with the LS head's exhaust port configuration.
Choosing the Right LS Heads
Not all LS heads are created equal. Factors to consider when selecting LS heads for your small-block include:
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Casting Number: Different casting numbers indicate different port designs and flow characteristics. Research thoroughly to find heads best suited for your performance goals.
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Chamber Volume: The combustion chamber volume affects compression ratio. Selecting the appropriate chamber volume is essential for optimal performance and to avoid potential issues like detonation.
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Budget: LS heads vary significantly in price depending on their condition and modifications.
Installation and Tuning
This is a complex modification that requires mechanical expertise. Proper installation involves precision work and the use of specialized tools. After installation, professional engine tuning is highly recommended to optimize the engine's performance and ensure reliability. Incorrect tuning can lead to engine damage.
Conclusion
Swapping LS heads onto a Chevy small-block offers a significant power upgrade, but it's not a simple bolt-on modification. Careful planning, selection of the correct components, and professional installation are crucial for success. The rewards, however, are well worth the effort for those seeking substantial performance increases from their classic Chevy small-block. Remember to always consult with experienced engine builders for guidance and support throughout the process.
