Ford Barra 4.0L Stage 1 Valve Springs (up to 460rwkw)
These Stage 1 valve springs suits all BA/BF and FG Ford DOHC 6 cylinder Barra 4.0L engines. These springs are suitable for applications up to 460rwkw, any higher power goals require a Stage 2 set of springs (see related items). These springs are highly recommended for applications over 300rwkw (400hp), to help eliminate valve float. Valve float causes damage to valve stem seals and collets / retainers. Once installed, a much more powerful and free revving top end power curve is possible. OEM valve springs have approx 50 psi seat pressure, once 15 psi is added to this equation (which acts against the valve spring), approximately only 35 psi seat pressure is left. This is nowhere near enough to keep the valves shut at high rpms. 85-90 psi installed height of the new springs, some 75% more stiffness over OEM. Premium quality – We guarantee these to be the best quality bee-hive style valve springs available on the open market!