We broke a stock block at the #2 main with 420RWHP to the tires....NATURALLY ASPIRATED.
Seen them break on the dyno stock, also seen them take 550RWHP....
With a stock block it is a guessing game as to when it will break, with a blower you are putting a lot of added stress on the front of the motor. The TUNE is critical, along with many other things.