These new aftermarket cylinder heads have gone through a series of tests to ensure we put our name on a trustworthy product. We have tested the quality from multiple sources and made adjustments that suit the customer's needs. All of our cylinder heads arrive bare and go through multiple tests before the heads are assembled. Our machine shop allows us the ability to correct any issues throughout the assembly process. Our Oring heads are surfaced and cut on our Rottler F69A CNC machine to guarantee a flawless product. After assembly, every head is vacuum tested to ensure the valve to seat pressure is within specification without a possible sealing issue. These heads are assembled in-house with all new components, including nitride intake and exhaust valves, seals, springs, retainers, and locks. We have the ability to install our heavy-duty springs or make the modification at the customer's request. 2 Brand New O'Ring Cylinder Heads Loaded with Valves, Springs, Seats, Seals, Retainers, and Keepers These Cylinder Heads include Hardened Seats and Injector Cups. The new casting strengthens the areas around the glow plugs and the seats to help prevent cracks. Gaskets and Studs available Limited 1-Year Warranty