The Edelbrock #61389 Performer RPM cylinder heads are designed for use with 1989-98 Holden VN Commodore 5.0L engines applications. The Edelbrock #61389 Performer RPM heads are perfect for street performance, daily drivers, street rods and muscle cars where seat-of-the-pants performance is needed. These cylinder heads deliver great throttle response and power from 1500 to 6500 rpm. They also feature the highest quality intake and exhaust valves and valve springs. For use on pre-pollution controlled vehicles only.INSTALLATION NOTE: • EQUIPPED WITH SPRINGS FOR USE IN HYDRAULIC FLAT TAPPET CAMSHAFT APPLICATIONS • Capable of 500+ horsepower on pump gas. • Intended as a direct replacement for factory heads and is configured as an easy bolt-on part for 1989-98 VN Commodore engines and as an upgrade to all earlier Holden production engines. • Features an extra thick 11/16" deck.