Weiand Pro-Street Driven Serpentine Pulleys WM6890Weiand Pro Street Driven Serpentine Pulleys10 Rib, 2. 85" WM6890 6890 Weiand 10 Rib Pro Street drive upper pullley 2. 85" Weiand developed the first ever aluminium intake manifold in 1937. Thirty years later Weiand developed complete blower drives for the GMC 6 71 supercharger. Today, Weiand is still at the forefront of intake manifold and blower development as well as high flow water pumps. To make more power you have to get more air to your engine.