Here's a chart from Hughes webpage for 'Super Prepped' RHS heads with 2.02 intake valves. Probably similar to what IMM does.
Lift Stock Super Prepped CFM Change Stock Super Prepped Change
.550 262 271
Here's an older chart for unported W2s from SDSS. This chart is for a 2.02" intake valve so the larger valve that I have will probably yield slightly better results. Clearly the potential is there for some big numbers but it's going to take a lot of grinding ($$) to get 'em there.
LIFT--------AS-CAST---------PORTED
.550”------258.4/155.2---------303.9/213.9
See the dilema? They're pretty close if you're racing flow benches. Besides, my cam only opens the valve .531" after lash so anything over that is irrelevant.