Big engines pumping out major horses need a solid connection between all that power and the rear wheel. That’s where JIMS’ new Cruise Drive Trap Door & Shifter Shaft Upgrade Kit comes into play. Designed for all 6-speed Twin Cam transmissions, by using an upgraded 6061 precision-machined trap door that holds transmission shaft centerlines to within .0005” and incorporating wider, heavy-duty bearings the kit is able to maintain centerline integrity and handle heavier torque loads. Those beefier bearings are held in place with beveled retaining rings to eliminate endplay while two solid true-centerline shift-fork shafts are included to replace the OEM hollow shafts for additional rigidity and strength. The suggested retail is $303 for the kit in either a black or silver finish cover.