All models of the Saginaw gearbox use one needle bearing and one bushing on the sector shaft. When we install our 3-Bearing kit, we machine the housing to accept two needle bearings, then also replace the top cover with our Billet version that has a third needle bearing in it instead of the bushing that is in the stock top cover. This makes for a much more durable steering gearbox and lets the sector shaft rotate more smoothly. Additionally, by placing the seal between the bearings it lessens the chance or leaking due to deflection of the sector shaft under load. This is something we do to every race car gearbox we build. Take a look at the cut-a-way photos below to see what tie differences look like. The needle bearings are marked in RED.