Normally I tend to agree with your posts YR but here I will just say this: In the case of exhaust testing I have tested enough to KNOW that I cannot predict the outcome of any exhaust test with 100% certainty. J.Rob
This is true. Exhaust is one of the most difficult things to sort out. My next W-2's will only have a 1.500 exhaust valve. I think 1.600 is just too big to keep the air speed up where it needs to be. So that's my plan. I'm sure the flow bench will say the 1.600 exhaust flows more, but it's nearly impossible to go by flow bench numbers on the exhaust port. The shape of the curve and how the port sounds, and the way it looks like with flow balls and my other ways of seeing what the port is doing is much more important than the actual number. As well as reverse flow and higher than normal test pressures.
Buy you are correct. I made a pretty blanket statement. But most of try time, dyno headers are better because they aren't all twisted up with tight turns at the flange to get them in the car.