i have to get a new water pump....

what is the difference between reverse rotational and the other?

i'm looking into changing to a march sbc setup; to do this they require i change my stock water pump.

i don't know enough about this subject so if anyone can shed some light i'd appreciate it!

 

A reverse rotation pump is just that. The serp. belt runs around it backwards which in turn spins the pump backwards. Depending on how you run your belt when you get through will decide the water pump you need.

 

It's possible that the March setup needs a short water pump as opposed to a long (stock).