Need big block help

Larry, my 500 dyno'd at 550 HP and 610 TQ with iron heads, and one step larger comp cam. The same shop built another engine after mine using the same comp cam as your friends, but with Edelbrock heads and it made similar horsepower but torque increased to 650. It could just be the different dyno, but those numbers appear pretty low. And yes it would pull to 6000 RPM, but power peaked around 5500.