Tapered extra thin 3/8" (9.53mm) 4130 chromoly heat treated pushrods with 3/8-24 nut with 24 threads per inch. With .145" (extra thick) wall thickness; recommended when extreme valve spring pressures are used. Manufactured with precision concentricity. The individual length intake & exhaust pushrods assures minimizing adjustment extension for increased stiffness and rigidity for maximum valve lift under high RPM loads. Pushrods can be adjusted 0.225" longer than stock to accommodate longer cylinder and smaller base circle camshafts. • Maintain maximum valve lift!• Increased stiffness and column rigidity maximizing valve-train stability; increasing engine RPM horsepower and torque output.• Adjustable pushrods are tapered 3/8" 4130 chrome moly adjustable pushrods; use a minimal adjustment parameter eliminating flex and loss of valve train-stability problems associated with most adjustable pushrods. • Individual length intake & exhaust pushrods keep the adjustment extension to a minimum • Designed to exceed the needs of performance engines using larger lift camshafts and high spring pressures; while maintaining proper and critical oil flow to top end valve gear • Race Series pushrods have 24 threads per inch with 0.145" wall thickness - recommended when extreme valve-spring pressures are used • Designed for use with hydraulic or solid lifters and street or race engines • HP+ and RACE SERIES pushrods require removal of rocker covers and rocker arm supports • FEULING pu