Found this:
http://www.etheads.com/00products.htm#

Click on the b1 bs link and it shows flow numbers.
They have some testominals from Koffels.
I talked to them, but have not used them.
I believe the shown flow numbers are ported to max wedge port size, not sure on valve diameter, but smaller 11/32" valve stems compared to the stock 3/8".