The sweet 1998 Ford Mustang from the 63376 is gaining the best power increase for the money by changing the rear axle gear ratio to 3.73 to 1. This means that the driveshaft will have one more full revolution for each revolution of the tire, getting the power curve into a more usable area. Chris installed the Yukon Gear ring and pinion gearset, Yukon Master install package, Yukon 1541H alloy shafts and Ford Motorsports positraction differential. The gears are set up using Ford's original pinion depth gauge set. We should be seeing fresh black marks, two lanes wide, in the St. Peters area in about 500 miles!