The Speedmaster MidRise Air design features the identical plenum and runner design as the normal MidRise. The main difference is that there is an open area under the plenum chamber. This feature is sometimes called an air gap design. The air flowing under the plenum provides a cooler charge for the incoming air with less heat transfer from the engine. This cooler air charge provides additional power and torque.

This Speedmaster MidRise Air for the Vortec features wider design to accommodate the Vortec design heads and also features the Vortec port configuration. The manifold also has a square bore carb pad to utilize the standard Holley, Carter and Edelbrock carburetors. This manifold is intended for use on up through -95 blocks using the 1996 and later Vortec (Gen 1+) heads or Edelbrock E-Tec heads. It can also be used on -96 and later Vortec engines with some minor modifications. The modification is not to the manifold itself. It just requires running a short section of hea