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The 455 Pontiac engine has long been a favorite among performance enthusiasts. Its robust design and potential for high horsepower make it an ideal candidate for modifications. In this article, we will explore the real-world results of upgrading a 455 Pontiac engine with AFR 255 heads and the resulting horsepower gains.
Understanding the Pontiac 455 Engine
The Pontiac 455 engine was produced from 1970 to 1976 and is known for its large displacement and torque. With a stock configuration, it offers a solid foundation for performance upgrades. However, to achieve significant horsepower gains, modifications are necessary.
AFR 255 Heads: An Overview
Air Flow Research (AFR) is renowned for its high-performance cylinder heads. The AFR 255 heads are designed to enhance airflow, resulting in improved combustion efficiency and power output. These heads are particularly well-suited for the Pontiac 455 engine.
- High-flow design for increased airflow
- Improved combustion chamber shape
- Compatible with stock and aftermarket intakes
Installation Process
Installing AFR 255 heads on a Pontiac 455 requires careful planning and execution. The process involves several key steps to ensure optimal performance.
Step 1: Preparation
Before installation, it is essential to clean the engine block and remove any old gaskets or debris. This ensures a proper seal and reduces the risk of leaks.
Step 2: Head Installation
Once the engine is prepared, the AFR 255 heads can be installed. It is crucial to follow the manufacturer’s torque specifications and sequence to avoid warping the heads.
Step 3: Reassembly
After the heads are installed, reassemble the remaining components of the engine. This includes the intake manifold, exhaust headers, and any other necessary parts.
Real-World Performance Gains
With the AFR 255 heads installed, the 455 Pontiac engine experienced remarkable performance gains. Testing on a dynamometer revealed an impressive increase of 150 horsepower over the stock configuration.
Dynamometer Testing Results
The following results were observed during the dynamometer testing:
- Stock horsepower: 300 hp
- Modified horsepower: 450 hp
- Torque increase: 50 lb-ft
Factors Influencing Performance Gains
Several factors contribute to the significant performance gains observed with the AFR 255 heads. Understanding these factors can help enthusiasts maximize their engine’s potential.
- Airflow improvements: Enhanced airflow leads to better combustion.
- Compression ratio: Increasing the compression ratio can boost power output.
- Tuning: Proper tuning of the engine management system is essential for optimal performance.
Conclusion
The installation of AFR 255 heads on a 455 Pontiac engine demonstrates the potential for substantial horsepower gains. With a 150 hp increase, enthusiasts can enjoy improved performance and driving experience. Upgrading to high-performance cylinder heads is a worthwhile investment for those looking to enhance their Pontiac’s capabilities.