Here's the first episode of Shin Mazinger Shougeki! Z-HEN that aired on HEROtv that replaced School Rumble and on GMA that replaced Hajime no Ippo: A New Challenger.
In case you are wondering why I placed GMA on the title, it is because this is the version that GMA also aired. Note, Shin Mazinger Z is dubbed by Telesuccess Prod., thus it is no surprise that you are hearing the same dub.
Special Thanks to sandies