Pontiac 326 350 389 400 428 455 MID-AIR™ MidRise Aluminum Intake Manifold [Polished] They're available in -3 AN

They're available in -3 AN sizes in a variety of lengths

These gaskets feature superior-quality rubber and steel

Speedmaster one piece silicone rear main seal

Speedmaster idle air control motor adapters allow GM-style idle air control motors to be used with throttle bodies originally designed for a different bolt pattern

enhancing overall performance and efficiency

Pontiac 326 350 389 400 428 455 MID-AIR™ MidRise Aluminum Intake Manifold [Polished] They're available in -3 ANThe 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.