The Mercury Racing SST-120 V6 2-Liter outboard is a legendary engine in tunnel boat racing, celebrated for its performance, reliability, and advanced engineering. Designed for the Formula 2 (SST-120) racing circuit, this engine, introduced in the late 1980s, has powered numerous racers to victory and remains a sought-after choice for both competitive and recreational use.
Its lightweight design, high RPM capability, and dependable construction made it the backbone of Formula 2 racing, setting a standard for performance in the sport. Even today, the SST-120 is prized by active racers, outdoor drag racers, and tuners who appreciate its enduring appeal and potential for modification.
In a new development, Buckshot Racing #77 is posting the race porting specifications diagram for the SST-120 available to tuners, hobbyists, and outdoor drag racers. While these specs are already familiar to professional SST-120 teams, this initiative provides those outside the professional circuit with detailed insights into the optimal dimensions and timings for rebuilding and modifying their Mercury 2.0-Liter outboards, including the AA Fat Blocks, earlier XR2 2.0 Liters and the original 1976-1977 1750 Black Max.
These porting specifications offer tuners and enthusiasts a chance to maximize the performance of their engines, whether for drag racing, restoration projects, or recreational competition. By providing this information, Buckshot Racing hopes to empower the broader racing and tuning community, ensuring that the SST-120 continues to perform at its peak for years to come.
The SST-120 was designed as a 60° V6, 2-stroke outboard with a displacement of 2.0 liters (122 cubic inches), a bore and stroke of 3.125 inches by 2.65 inches, and a compression ratio of 10.0:1. It produces approximately 190-215 HP and operates at up to 7,500 RPM, making it ideal for high-speed racing applications.
The engine uses a dual-throat carburetor for fuel delivery, paired with a high-performance electronic CDI ignition system for precise and reliable timing. It runs on a 32:1 fuel mixture of high-octane racing fuel and 2-stroke oil, with a water-cooled system to maintain consistent performance under demanding conditions.
Weighing approximately 330 pounds, the SST-120’s compact design enhances aerodynamics and handling, particularly in tunnel boat configurations.
The SST-120 is built for high RPM performance, ensuring exceptional speed and acceleration during races. Its lightweight design contributes to a superior power-to-weight ratio, while the precision ignition and optimized cooling system allow it to handle the intense demands of competitive racing.
These features have made it a standout in its class, solidifying its reputation as a reliable and high-performing engine.
The legacy of the SST-120 is undeniable. Its influence on the competitive Formula 2 scene and continued use in vintage and amateur racing reflect its lasting value.
For tuners, hobbyists, and outdoor drag racers, the availability of porting specifications offers an exciting opportunity to push the boundaries of what this iconic engine can achieve.
Mercury Racing’s SST-120 remains a testament to the company’s dedication to innovation and performance, providing enthusiasts with a compelling mix of history, engineering excellence, and ongoing relevance.
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