I have them. Only been to the track once and the new E-85 carb was running rich. I think they flowed around 385 at my cylinder head guys bench, but that was without any entry form and I think on a 4.30" bore?
I think they out flow my single 4150 1,000 cfm carb? The car ran nearly the same ET as when I had my 335 cfm heads on the car (but as mentioned, there is more in the new engine once I get it tuned.)