Horsepower limit for out of the box Edelbrock RPM heads

I don’t feel trying to think about it in terms of an actual “limit” is practical.

Think about what you’re trying to build, and then determine if that type of head fits with the rest of the combo.
Flow benches and engine dynos can vary greatly........however, I would say if you’re looking to make upwards of 500hp, and the rest of the build is on target with that type of power output, the unported RPM’s could get you there.
The one caveat being the flat tappet springs.
At the installed height they come set up at as delivered from Edelbrock, they’re not going to provide enough load to allow many of the popular faster rate cams to operate effectively at an rpm high enough to get comfortably into the 500hp range.

Basically.......valve float before the power curve reaches its peak.
Or, looking at it another way, a premature artificial peak because of compromised valvetrain control.