Interesting video RPM Airgap intake flow.
So, since you guys know all this... is there any point to having a head that flows 300cfm if your intake can only do 240?
(With an asterisk!) The engine will respond better because the head is better but not being fully utilized. When a head porter works his magic, the magic starts with the valve. The valve & seat gets worked on and then the bowl area. The quality, read that again, the quality improves as well as the air flow. It’s all in the shape and area of the work done.
Now, if the bowl work flows more than the intake, there will be only a gain until the intake can not supply more air and fuel. Now IF the intake can flow enough air and fuel beyond the valve, valve seat and bowl work, the next in line (depends on who is porting) is the short side radius. This is often included but not always. Then the work goes up the port into the area you can easily see when holding the head.
Now, since the intake can flow well to 200 cfm, the amount of A&F flowing through the head can improve and more power can be made.
The RPM has shown to be able to make some really good street power numbers. The A&F must be getting through to be able to make that power. How? In this area, I can not offer much help.
But it’ll have something to do with the ram effect and the amount of time the valve is open. The intake is known to be able to make over 500 hp.
As I said earlier, (perhaps in another post/thread) this is why I had John port my M1 single plane. It is going on an engine that will see sizable camshafts and increased compression that will take advantage of not only a single plane but a well ported one.
If you’re in your he street, use a dual plane and (IMO) camshafts under 240@050. Over 240, you may - MAY - like a single plane intake. A lot depends on what you’re doing with the car. A single plane will really like a cam in the mid 250’s and larger.
Despite the seemingly low flow combo, it’ll still make power. The owner of the heads is looking for 400+ HP, he can get there. He may not like the combo to get there though.
A little more insight in this thread on intake porting.
Some M1 porting pictures and flow numbers