Ford racing gears for $350 installed! 3.73 or 4.10 Gear Ratio for your 79-04 Solid Axle Mustang Get the most out of your engine by changing your ring and pinion gears. You can alter the RPM where your engine operates by increasing the gear ratio. This will allow you to accelerate faster, tow more easily and burn rubber with ease. *Additional Pricing may apply if bearings are needed.