Manley Street Flo valves are excellent-quality valves at an affordable price. All are made from stainless steel (intakes are NK-841; exhausts are XH-424) with chrome stems and hardened valve tips. Street Flo series valves are fully machined and swirl polished, and both the materials used and the heat-treating process are superior to those of the Budget replacement series valves. They're available in a variety of head diameters, with either straight stems or undercut "Pro Flo" stems for increased flow. Order the set that's compatible with your vehicle and engine application.