![Speedmaster® 1-147-074 Pontiac 326 350 389 400 421 428 455 MidRise Air Intake Manifold [Polished]](https://product-arena.s3.us-west-1.amazonaws.com/Speedmaster/1-147%20Intake%20Manifolds%2C%20Carbureted/1-147-074/1-147-074.jpg)
![Speedmaster® 1-147-074 Pontiac 326 350 389 400 421 428 455 MidRise Air Intake Manifold [Polished]](https://product-arena.s3.us-west-1.amazonaws.com/Speedmaster/1-147%20Intake%20Manifolds%2C%20Carbureted/1-147-074/1-147-074_A.jpg)
![Speedmaster® 1-147-074 Pontiac 326 350 389 400 421 428 455 MidRise Air Intake Manifold [Polished]](https://product-arena.s3.us-west-1.amazonaws.com/Speedmaster/1-147%20Intake%20Manifolds%2C%20Carbureted/1-147-074/1-147-074_B.jpg)
![Speedmaster® 1-147-074 Pontiac 326 350 389 400 421 428 455 MidRise Air Intake Manifold [Polished]](https://product-arena.s3.us-west-1.amazonaws.com/Speedmaster/1-147%20Intake%20Manifolds%2C%20Carbureted/1-147-074/1-147-074_C.jpg)
Speedmaster®
Pontiac 326 350 389 400 421 428 455 MidRise Air Intake Manifold [Polished]
Overview
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.
Specs
| Brand: | Speedmaster |
| Part Number: | 1-147-074 |
| Part Type: | Intake Manifolds, Carbureted |
| Product Line: | MidRise Air |
| Engine Block Style: | Stock/OEM standard deck |
| Carburetor Quantity: | One |
| Intake Style: | Dual Plane |
| Basic Operating RPM Range: | 1,500-7,500 |
| Intake Manifold Height: | 6.500 in. |
| Intake Material: | Aluminum |
| Intake Finish: | Machined Polished |
| Carburetor Base Plate Gasket Included: | Yes |
| Square to Spread Bore Adapter Plate Included: | Yes |
| EGR: | No |
| Quantity: | Sold individually. |
| Notes: | Works with spread and square bore carburetors. |
| Calculator: | CFM Calculator |
Prop 65 Warning
This product may contain chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.