How reliable is Desktop Dyno?

I do think a intake manifold selector would be awesome!
They also need to update the cam selections (even though every possible measurment is changeable).

My other questions are:

What does the factory 5.9L Magnum have for induction flow in cfm? (my 2001 Dodge Ram 5.9L; all stock)

Trying to figure out my induction flow cfm for my 406 Big Block.
It uses an Edelbrock Performer RPM intake and a Holley 750 / 770 cfm carburetor?

Trying to figure out my induction flow cfm for my 360 Small Block.
It has an Edelbrock RPM Air Gap intake manifold and a Holley 650 / 670 cfm carburetor.
What if I use a 750 / 770 CFM carb.?