Pontiac 326 350 389 400 428 455 MID-AIR™ MidRise Aluminum Intake Manifold [Polished] Speedmaster has redesigned the power

Speedmaster has redesigned the power gear sets to incorporate four pinion gears--unlike a stock 3-pinion style--to increase their load-handling characteristics

This manifold will typically produce more power than any similar competitive manifold due to larger ports and runners

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

They are manufactured from machined steel and offer excellent valve spring location

Pontiac 326 350 389 400 428 455 MID-AIR™ MidRise Aluminum Intake Manifold [Polished] Speedmaster has redesigned the powerThe 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.