Oldsmobile 400 425 455 MID-AIR™ MidRise Aluminum Intake Manifold [Black] They are made from stamped

They are made from stamped steel and feature a chrome plated finish for good looks and durability

These aluminum housings simply replace the stock cast iron housing

The quick spool system can be initiated via a switch

but not included

Speedmaster high quality aluminum replacement air horn kit to suit downdraft manifolds

Oldsmobile 400 425 455 MID-AIR™ MidRise Aluminum Intake Manifold [Black] They are made from stampedThe Speedmaster MID AIR design features the identical plenum and runner design as the normal mid rise. 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.