Intake manifold design

[SShep71]

There are MANY aspects of the design of an intake manifold, it is similiar to intake port design. Its all in what you want the part to do. The over all design (single plane, tunnel ram, tubular, etc) all have good points and bad points. It basically comes down to three things, Volumetric Efficiency, Runner Velocity, and CFM. If you just want to put an intake together for the cool points and the experience its not a problem, but like any system the whoole system is only as good as its weakest link. To properly build an intake you can start at the cam, or start at the heads. The flow characeristics of the intake have to MATCH/COMPLIMENT the flow characteristics of the heads, and the capabilities of the cam. You can do all the computer modeling you want to reguarding flow characteristics but until you put your intake on a flow bench you will never understand how it actually works. The reverse header you referanced is exactly what those tunnel rame intakes are essentailly. Each individual port is a runner and the collector is the large center section. It is designed like this to keep the volume and flow consistant over each port.