In stock form this Hi-Rise cast iron intake manifold will produce more power than any other stock Chevy cast iron intake manifold. Commonly referred to as a “Marine” intake, this manifold is a cast iron copy of a Z-28 high rise aluminum intake. It is equipped with Holley and Q-Jet carburetor bolt patterns.  It will not bolt to Vortec or Vortec Bow-Tie heads. Unfortunately, we no long offer this intake manifold; it was discontinued by Chevrolet in 2012.  You can usually find these intakes on E-Bay.