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What size bench does Chapman Flow on, and what is Dwayne using these days? I do recall Dwayne telling me ages ago, but I can't remember everything, lol. I do recall Dwayne's bench being conservative regardless.
AL...

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actually the better question would be..
what size bore fixture was used?
what was the elevation, pressure?
airflow temps?
;these would be the biggest factors in seing different #s from one to another.
you have to understand conservative is relative.
now this is directed at no-one, just in general.
people have to understand.
proper bore fixture diameter, if not the same will show different results,too small for the heads application "can cause the stall" or lower peak #s
elevation in reguards to sea level is one of the biggest factors for the difference.
id say thats the biggest source of the confusion.
next would be the correction factors.to try to compensate..
just my 2 cents.

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everyone is an expert

i think you need to do a little more homework on flow bench design before you start casting a shadow of doubt about whether or not flow data is directly comparable or not.
not all flow bench designs require corrections for weather variables.

from the Superflow website;
"the flowbench measures the ratio of the pressure difference across the orifice, to the pressure across the valve. Both the orifice and the head see air at the same temperature, density, and humidity. A flowbench of this design provides results, which are independent of the atmospheric conditions. In fact, if you put a cylinder head on the flowbench, and run it at a barometric pressure of 24" of mercury, and run it later at 29" mercury, with the same cylinder head, you will get exactly the same flow numbers. You don't have to correct for temperature or correct for pressure. "

my own personal opinion is that you cant directly compare results from any two flowbenches as being 100% equal.

i dont really have anything else to add at this point about these heads.
i was hoping to get some measurements off them today, but as it turned out, i was on the dyno all day.

the bowls "appear" to be pretty generous on both the intake and exhaust side, and there is much more height on the intake short turn than on the original VI's like what were used for the EM470 motor.
i'll paw through my notes and see what the best port on the EM470 heads was for comparison.

as for the port stalling at high lifts....thats more of a "welcome to my world" kinda thing.
the short turn doesnt "feel" like one that would make it to .800 lift on my bench without stalling...and it didnt.
on a bigger bench...who knows.
regardless....these things are pretty impressive in the mid-lifts.
they really put the hurt on the SR's, 440-1's, BD's, in those lower mid-lift ranges....and are impressive up top too.

the only concern i would have with these on a larger CI motor like what Wize is going to build is the port cross section of the exhaust port.
it appears to be a fair amount smaller than a good flowing SR or 440-1....and sometimes when there is a lot of volume to deal with(like on a large displacement motor)....they just need to be bigger.
from the looks of the flow numbers for all 3 versions of the Chapman VI's on the Chapman site, the exhaust ports are done the same for all of them. im sure its overkill for the small version, really good on the middle version....but i feel is a tad small for this version.

i'll have to test it with a 2" tube on it to see how it responds.