World Products uses Manley race series performance valves and are a great choice for your bracket, oval track, or high performance street engine. All valves are made from stainless steel (intakes are NK-842; exhausts are XH-426) with chrome stems and hardened valve tips. In addition to being made from high-quality materials, Race series valves are swirl polished and fully machined. Manley Budget series performance valves are high-quality valves at very affordable prices. All are made from stainless steel (intakes are NK-480; exhausts are XH-422) with chrome stems and hardened valve tips. They're also swirl polished and fully machined. Both the materials used and the heat-treating process are superior to original equipment replacement pieces. These valves are available in stock length and 0.100 in. longer. Manley Street Flo valves are excellent-quality valves at affordable prices. 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 with either straight stems or undercut "Pro Flo" stems for increased flow. Manley Race series performance valves are a great choice for your bracket, oval track, or high performance street engine. All valves are made from stainless steel (intakes are NK-842; exhausts are XH-426) with chrome stems and hardened valve tips. In addition to being made from high-quality materials, Race series valves are swirl polished and fully machined. Manley Severe Duty series performance valves are a great choice for your high performance or race engine. All valves are made from stainless steel (intakes are NK-844; exhausts are XH-428) with chrome stems and hardened valve tips. Severe Duty series valves are made of superior materials, are fully machined and swirl polished, and are available with either undercut "Pro Flo" stems or straight stems.