Review on 🔧 BBK 1603 Underdrive Pulley Kit for GM Truck - 3 Piece CNC Machined Aluminum, Suitable for 4.3/5.0/5.7L Engines by Aaron Carney

The outer edge of the crank pulley was notched resulting in a slight deviation from the belt track. I asked for a replacement (never done here) and got it quickly thanks to Revane for that. The pulleys are very good, but I was a bit disappointed with the performance gain. I'm sure it's mostly because I've already removed the 6.5lb clutch fan and installed FF Dynamics electric fans (wow!). Also, I'm a bit concerned that the alternator pulley is thicker so the nut can't be screwed all the way in. I would recommend replacing the running lights with LEDs to compensate for the slower charge rate when idle. 1989 GMC K1500 5.7L