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

We ran a '72 360 block,filled with a girdle,over 1100 1/8 mile passes before the cast 4" crank finally broke.It broke just before the 6500 shift point,and the only damage to the block was where the #7&8 rod dinged it! this engine made 639 h.p. but we never turned it past 6800