March pulley?????

[jimmyz18]

My dad has a 71' Mach 1 with a 427 based block. He recently put the March polished aluminum pulleys on it, crank, water pump, and alt, switching from a V-belt to a serpentine. The water pump is a Edelbrock. What is happening is under a load, ie burnout, (showing off in front of friends) or heavy acceleration the snout of the water pump breaks off and destroys everything, even putting a hole in the hood. Has anyone had this problem? or have any ideas what could cause this. The car is fine just normal driving. This is the second time it has happened.
Thanks
Jim