Some years ago I flowed a set of edelbrock heads with minimal intake port work that flowed 300 cfm at 28" of water on a SF 1200 bench that was calibrated to be within 1% of Ford's 3 million dollar bench.
http://www.flowsystemsinc.com/index_products.htm Then click on automotive then on Intake and exhaust manifold and cylinder head.
That being said, the VICTOR 850 Intake flowed within 1% of the head and the Victor 1050 flowed with-in 2%. The RPM was with-in 3% of the head. 97% times a 300 cfm head is a 297 cfm Intake. A Pretty Good Intake.
I also flowed a lot of other heads and intakes over a two day period. The Torquer II flowed about 262 cfm.
Tom V.