Actually no,not at the same time.I did things backwards--LOL, First I got a 2800 stall converter(stallion).Before I got it, my car was bone stock,93 LX aod,the car wouldnt even leave a little rubber off the line(NOTHING).Now getting traction was a problem,major league difference!Then I got 3.73 gears and a trans go shift kit put in at the same time.Another major league difference.It still smokes them,only now it pulls pretty hard so Im not just sitting there spinning the tires.My old gears were 2.73's.Im real happy with its performance!