**600hp sbm block limit? Or is it bs!!**

High Rpms will kill a block a lot faster than hp. You will have more stress at 500hp at 8,000rpms than making 700hp at 7,000rpms. Which the pic of the blocked cracked probably came from a circle track/dirt track car spinning 8,500+. They are limited to certain parts not Rpms.

My 2 cents