Originally Posted by
Warren Stramer
About posting flow numbers; I have not for a number of reasons, For one, I could do like some (not referring to anyone in particular) and post made-up numbers that makes me look like a porting god. Or, If I posted the actual numbers and they were Lower, or higher than expected some might mistake the data for a model to avoid, or the benchmark for all other 8 valves to copy, and it is neither.
You could make one of these intake ports flow like a sewer pipe on the flow bench, but make less power on the track than with a properly sized and shaped port-seat-chamber.
In my opinion (My opinions are only good for about 90 days) comparing flow bench numbers are nearly meaningless.
The bench is about the last tool I use when laying out a good performing head. I am NOT saying they are useless, they definitely have their place, but they do not replicate a running engine, not even close. IC engines are not steady-state flow pumps, and the actual flow through an engine is at a FAR HIGHER depression than anything you will achieve on a typical flow bench.
What they are good for is determining relative flow profiles at various valve lifts, flow velocities, and flow bias, and I make good use of mine for that. Just need to understand their limitations.
Over the years I've seen 8valve flow numbers on the forums and for example someone may have a head that flowed say, 190cfm @.500 or so on, but then they are lead to believe by 'convention' that they should run a cam that can only yield maybe .450 valve lift; They wasted their time porting for .500 because the head will never see it. They should have concentrated on flow around .450 or less. Or better yet, get a cam that opens the valves to at least .500.
My point is, take the flow bench numbers you read with a grain of salt. There are more important aspects to a powerful cyl. head.