Sorry, but I can't find it. I was looking for it last night. IIRC it was a 5.0 or MM&FF Magazine article. I thought that I downloaded the jpeg of the table of flow #'s but I can't find that jpeg either.
It was a fantastic article, it gave stock flow #'s for the PI 2V heads, original Cobra 4V heads, 3V heads and the Mach 1 heads. The Mach 1 heads flowed the best. The 3V heads flowed about as well as the old Cobra 4V heads.
Then there were flow #'s with the heads ported.
I will search again to see if I can find the jpeg of the flow #s table. Maybe someone with more free time them me can search here on Stangnet for the original thread and link. I think that it was posted back in October. Or maybe someone with that 5.0 or MM&FF mag can check in.