Edelbrock 7581 Performer RPM Air-Gap Intake Manifold Patented runner tuning and a 180 degree firing order Features the air-gap design for the ultimate street performance Ranges from 1,500-6,500 RPM Aftermarket 4-bbl carburetors are not compatible with Auto Overdrive Transmission (AOD) unless used with Lokar bracket SRK-4000 Includes nitrous bosses and has no provision for exhaust heated chokes and no exhaust crossover