3. We deliberated a bit on the gears and ultimately settled on a 3.50:1 ratio (PN YG F9-350). The 2011-and-newer Coyote-powered Mustangs come standard with a 3.55:1 ratio, and an optional 3.73 gear is available. Keep in mind that these cars also wear taller 28-inch wheel and tire packages. We’ll be going with something in the 25- to 26-inch range, so the 3.50 gear should provide a spritely twist of the engine on up to 7,000 rpm. Here, Donnie Green has pressed on the pinion bearing and added the provided solid spacer. Where the factory setup uses a crush collar to set the pinion preload, many companies opt for this spacer, along with a number of steel shims, as the combination will not distort or compress under hard launches or acceleration.