Proflow's AirDual intake manifold is designed for street 253-304-308 c.i.d. Holden Commodore V8 engines. This intake manifold is a dual-plane design that is tuned for excellent throttle response from idle to 5500 RPM, aiding in fuel vaporisation and increasing volumetric effiiciency. Designed to fit both early and late cylinder head bolt hole patterns, pilot holes have been drilled on each side of the exhaust crossover. Accepts both square-bore and spread-bore carbs. Fits Red/Blue/Black engines. Does not have a provision for external heat crossover. These are available in natural or black powder coated cast-Aluminium finishes.