Port velocity average target fps?

273 said
I played around with your formula, works out Chad's formula is a simplified version, cfm x 2.4 / csa = average fps. 144/60= 2.4 now I see where his constant comes from was wondering that.

Basically a 6683 rpm 367 cid engine needs 300 cfm and a 2.25" csa giving an average 320 fps according to their formulas.

Question is, is that an acceptable fps for a street strip my guess it is, but to get the fps to where Eric says it should be 285 fps would need to be a 2.53" csa. But funny as he said 285 fps should be the goal and one of the heads he was comparing calculated to be that but actually speeds were way higher then that leading to believe there actually average was way higher.

I'm not overly worried about it, obviously we only got a few heads to choose from anyways.

I'm no cylinder head expert, but it seems to me that velocity will be a result and not necessarily something to target.
On a street/strip setup people have good luck with "too small" of a head than too large. Probably because bigger really only benefits at the top of the tach, it makes things worse elsewhere.
The formulas and numbers are good to ballpark things and spot check choices, but I wouldn't treat them as gospel either. For a street strip engine, it's probably OK to let the velocity run higher than you would for a dedicated racer.
Air has to accelerate with each valve event, and so lower target velocity can help when extreme rpms reduce the valve open time by reducing how much the air has to speed up. Obviously there's also resonant tuning impacts from the intake and the exhaust and are also significantly impacted by the cam, but all things equal the lower velocity port will pass more air through at maximum rpm. Of course, rarely do all other things remain equal!