The Spectre air intake plenum is designed to fit Holley Dominator carburetors with a 7-1/4 inch neck. This plenum is fabricated from high quality cast aluminum to withstand the pressures of boosted applications and has a polished finish for a show car look. The plenum is low-profile and measures 3 inches tall with 4 inch dual inlets that are 110 degrees apart that match up to all Spectre 4 inch tubing, filters and accessories. This product is not C.A.R.B. exempt. Products that are not C.A.R.B. exempt are legal in most states, but may not be used in California or states with similar emissions control laws except on pre-1976 vehicles.