PERFORMER 308 HOLDEN (IDLE-5500 RPM) Designed for street 253-304-308 c.i.d. Holden V8 engines. This Performer intake manifold is a dual-plane design that is tuned for excellent throttle response from idle to 5500 rpm. The Performer Holden manifold has been designed to fit both cylinder head bolt hole patterns. Pilot holes have been drilled on each side of the exhaust crossover for early or late model cylinder heads and will need to be drilled out depending on application. Will not fit EFI Heads. Accepts both square-bore and spread-bore carbs. Fits Red/Blue/Black engines. Does not have a provision for external heat crossover. Includes Edelbrock square-bore carb adaptor plate #2732, carb gasket and carb studs. * CARB RECOMMENDATIONS: OEM 4-bbl. Edelbrock Thunder Series AVS or Performer Series (600-750 cfm) Carburetor. ** Do not use high performance or competition type intake gaskets for street application. Due to material deterioration under street driving conditions, internal leakage of both vacuum and oil may occur. Recommended intake gasket: stock gasket set or equivalent. Manifold height: A-3.25", B-4.67"; Carb pad height: 3.96". Port exit dimensions: 1.07" x 1.83". For the heights of all Edelbrock manifolds, please visit the Manifold Reference Dimensions