1966 GTO Heads 093 and 092: A Comprehensive Review of Performance

The 1966 GTO was a high-performance muscle car that featured a number of advanced features for its time, including powerful engine options and advanced suspension and braking systems.

One of the key components of the 1966 GTO’s performance was its cylinder heads, which were available in two different versions: the 093 and the 092.

In this review article, we will take a closer look at these two cylinder head options and their impact on the overall performance of the 1966 GTO.

Overview of the 1966 GTO heads 093 and 092

The 1966 GTO heads 093 and 092 were both manufactured by General Motors and were designed to work with the 389 cubic inch V8 engine that was standard in the GTO at the time. The 093 heads were the standard option for the GTO, while the 092 heads were an optional upgrade.

The primary difference between the two heads was in their combustion chamber design. The 093 heads featured a 72cc chamber, while the 092 heads had a larger 87cc chamber.

This difference in chamber size had a significant impact on the engine’s compression ratio, with the 093 heads producing a ratio of 10.75:1 and the 092 heads producing a lower ratio of 9.75:1.

Performance comparison: 093 vs 092 heads

The choice between the 093 and 092 heads largely came down to a trade-off between compression ratio and airflow. The larger combustion chambers of the 092 heads allowed for improved airflow, which in turn could lead to increased horsepower and torque.

However, the lower compression ratio of the 092 heads meant that the engine would not produce as much power per combustion cycle.

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On the other hand, the 093 heads produced a higher compression ratio, which could lead to more power per cycle. However, the smaller chamber size meant that airflow was somewhat restricted, which could limit the overall performance of the engine.

In practice, the choice between the 093 and 092 heads often came down to personal preference and the specific needs of the driver.

I believe some drivers preferred the increased power potential of the 092 heads, while others valued the higher compression ratio and more responsive throttle of the 093 heads.

Impact on overall performance

Regardless of which head option was chosen, the 1966 GTO was an impressive performer for its time. The standard 093 heads produced 335 horsepower and 431 lb-ft of torque, while the 092 heads could increase these figures to 360 horsepower and 438 lb-ft of torque.

These performance figures were achieved through a combination of advanced engine and suspension technology, as well as the careful tuning of components like the cylinder heads. The 093 and 092 heads played a significant role in the overall performance of the 1966 GTO, and their design and performance characteristics have continued to influence engine design and performance to this day.


The 1966 GTO heads 093 and 092 were important components of one of the most iconic muscle cars of all time. While the choice between these two head options came down to a trade-off between compression ratio and airflow, both options offered impressive performance figures and helped to establish the GTO as a dominant force in the muscle car world.

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Today, the design and performance characteristics of these heads continue to influence engine design and performance, making the 1966 GTO a true automotive classic.