I can't tell you how many sets of Edelbrock heads I've had on my flowbench and here are the numbers. Now subtrack what you lose with your intake, lash, pushrod angle, and pushrod deflection.
Do you have the info on how that compares to an X head on your flow bench or an X with a little extra work in the bowls and a gasket match? I have read an Edelbrock head is close to an X head with some bowl work and a light gasket match.