SKU: FSHF9-557
MPN: F9-557
The Ring & Pinion Ford 9in 5.57 is a precision gear set engineered for serious performance builds and street/strip applications where final drive ratio optimization is critical. Built by FAST SHAFTS under part number F9-557, this 5.57 ring and pinion combination is designed for Ford 9-inch differentials—the industry standard for drag racing, road course, and high-horsepower street cars. Whether you're swapping into a classic Mustang, Fox-body, or modern restomod, this gear ratio delivers the aggressive acceleration and rpm matching required for boosted engines and power adders.
The 5.57 ratio sits in the sweet spot for naturally aspirated and supercharged platforms running 400+ horsepower, pulling peak torque into usable RPM bands without highway cruising penalties on longer gearing. Precision-cut ring and pinion teeth are manufactured to tight tolerances, ensuring smooth engagement, minimal backlash, and consistent power delivery under load. The Ford 9-inch differential housing accepts this gear set directly, making installation straightforward for experienced mechanics; proper setup with quality bearing preload, backlash shimming, and gear oil ensures longevity and eliminates noise. At 20.13 lbs, the gear assembly is lightweight yet robust, handling sustained track duty and repeated acceleration cycles.
This ring and pinion set is ideal for enthusiasts upgrading stock or worn differential gearsets, particularly those building dedicated weekend warriors or competition vehicles where launch rpm control and acceleration feel matter more than fuel economy. Installation requires professional setup—incorrect backlash or preload leads to premature wear and catastrophic failure. Verify your Ford 9-inch housing type and bolt pattern compatibility before ordering; this gear set is engineered for standard Ford 9-inch applications and demands quality installation with proper bearing spacers, crush sleeves, and finish with fresh synthetic 75w-90 or equivalent gear oil for optimal performance and protection.
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