Chevy GM LS3 Dual Plane 4150 MID-AIR™ MidRise Aluminum Intake Manifold [Polished] It is set up to

It is set up to accept a spread bore carb but comes with an adapter plate that permits the use of square bore carbs

most notably the cylinder heads

The runner length and the tapered cross-section were designed to perform well for a wide range of engine configurations

327 and 350 V8s with 1987-95 heads with OEM 4-bbl carb

Chevy GM LS3 Dual Plane 4150 MID-AIR™ MidRise Aluminum Intake Manifold [Polished] It is set up toThe 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.