Can anyone help me I have a 496 that the belt under rpm wants to slide then it schreads the belt. I have replaced the drive water pump still does it can anyone help. thanks chris

Start simple. Double check you installed all the small bolts back into the pump properly to ensure a good alignment of the pump pulley. If it's out of alignment, it will slide off like a bicycle chain would. Besides alignment, and proper tightness, there's no reason it should slide off.

i have seen on the newer models , that the springloaded belt tensioner gets bound up due to corrosion and lack of lubrication. this causes a bind spot if you will . then when under load at rpm the belt starts to flutter and pop off or shred or both.

good luck.