Fit’s 5.9L 2500 3500 Truck. Our Billet Aluminum Freese Plugs Allow you to run your factory fans without blowing your oem freeze plugs under big boost, high pressures, and high RPM. Included are the following: 3 Billet plugs to replace your OEM Plugs on the side of the Cummins block. 1 Front Block Fan Freeze Plug, and 1 rear plug with a. 1/2 npt threaded hole that allows you to connect to a coolant bypass system. All our Billet Freeze Plugs have the Viton Rubber O rings that are top quality along with Stainless Steel Bolts. To install the APP billet freeze plugs: Remove your factory side freeze plugs; clean the bore with scotchbrite (make sure there is nothing in the bore that can cut the o-ring). Thread the bolt into the plug retainer 2 full turns and install the plug in the block. The freeze plug should go in with hand pressure only.