The Small Block Windsor and 5. 0-liter engines are two of the most popular engine designs in the history of Ford technology. and now, RHS® has developed an impressive head series to provide Small Block Ford engines with increased airflow and horsepower no porting or modifications needed. RHS® Pro Action? Small Block Ford Cylinder Heads include more standard features than any Ford head in the industry, including premium bronze valve guides for extended valve sealing and durability. With a host of runner and chamber sizes to meet various performance needs, these heads are truly the race winner's choice. Designed for Small Block Ford 289-351 Windsor & 5. 0-liter engines; compatible with all OEM & aftermarket componentsSmaller valve package allows usage without piston modificationDual exhaust bolt pattern fits both stock manifold & large tube headersClean Cast Technology? provides better casting quality for minimized airflow restriction & improved airflow efficiencyPit Stop USA offers Racing Head Service Pro Action™ Aluminum Racing Cylinder Head - SB Ford - 200cc Intake Runner - 58cc Comb. Chamber - Intake/Exhaust 2.020", 1.600" - Bare 35012 at low everyday prices. Be sure to check out all of our products from Racing Head Service including Racing Head Service Aluminum Heads - Small Block Ford and RHS Aluminum Heads - Small Block Ford.