I was able to get the street gears to last 2-3 yrs foot braking before I broke the teeth on the pinion. I installed another set and got about a year on them when I switched to the trans brake. The Dart was 3150 lbs and ran in the upper 9's. When they finally became available, I ordered a set of 4.30 pro gears. Ended up purchasing another car in the off season and never used the gears. I was faced with replacing street gears every year or installing a set of pro gears. Since I never got the pro gears installed, I'm not sure how much more life they would have provided.