Freeze Plug 4 Pack - Side & Rear - E.D Billet - Cummins 5.9L & 6.7L 2003 - Present (EDC03PFPRBx4) -These machined Billet freeze plugs are perfect for your racing application! They bolt in so they will not blow out! -Helps prevent blow out at high rpms, a weakness of stock -freeze plugs. -Machined in house at Engineered Diesel! At Engineered Diesel, we believe there is always a better way to do something. Thats why we design and machine our own parts in house. When OEM doesnt get the job done, Engineered Diesel will. Whether you need a stronger alternative to a cheap OEM part or a custom part for your pulling truck, we have you covered!