| For those that missed it, I bought a set of MSP and a set of AMS manifolds. 
Due to time constraints, I was unable to cc the manifolds and I only tested the DS manifolds (cylinders 2, 4, and 6) Here is the setup on a Superflow SF-1020 flowbench: 
A local member (Kory Krofft) came with me to verify that I was doing the test in an unbiased way. The three ports were flowed separately at .300" lift (about the lift of stock cams) and 28" pressure. The head used to flow has been ported and Ferrea 1mm OS valves installed. I used an exhaust gasket and I blocked off the ports of the "down" cylinders to prevent air from flowing through them. Here are the results: MSP Cylinder #6 - 134.0 CFM (cubic feet per minute)
AMS Cylinder #6 - 133.7 CFM MSP Cylinder #4 - 155.8 CFM
AMS Cylinder #4 - 148.4 CFM
Stock Mani #4 - 110.4 CFM MSP Cylinder #2 - 166.5 CFM
AMS Cylinder #2 - 170.3 CFM Here are the results that AMS advertises: 
There is obviously something different in our setup. My guess is that their results were obtained at either a higher lift, or without exhaust valves. I am not saying they did it wrong, I am only saying that they did it differently. I will attempt to explain why the cylinders are so uneven. When flowtesting, if you test an open exhaust port, the turbulence when it leaves the port causes a loss of flow. If a pipe is placed against the face of the port, flow numbers increases substantially. The further up the manifold the port was, the more this effect took place. This is the reason that people run "equal-length" headers. It evens the flow of the cylinders. These numbers are yours to interpret. I am not going to offer any opinion about the whole issue. Kory or I will answer any questions that you might have about my setup. For the record, and Kory can verify this, Kory does not feel the same way about this issue as I obviously do. It is for that reason that I asked him to be present. One last thing, I noticed that people were asking about the metal used to cast the manifolds. If people really want to know the answer to this, I can break a piece off of the heat shield bosses and send them off to a metallurgist. If you are interested, please mention it in your response. I am not going to do this unless people truly are interested. Thanks for giving me your time.
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AMS vs. MSP Results - 
