I have become confuzzled about this... Been searching for about an hour and every post I read states that you need a reverse rotation pump with a serp belt. However, mine appears to use a standard rotation pump. The motor, I am told, came from an '86 F-body. I have not changed anything. I ask because I am helping a friend with his project. He bought a set of March brackets and it seems that his water pump is turning the wrong direction. We have been debating standard and reverse rotation half the night. (Google helped me with that) If my setup is factory correct he could just buy a water pump for my application ('86 Firebird) and he'd be set, but on the Autozone website it lists pumps for v-belts and pumps for serp belts. So, is there a way I can tell if it is standard or reverse rotation without taking it apart?

I found out that there are gaskets available for the back cover on a water pump, so I pulled mine off and had a look inside. There is really no way to tell which rotation it is without pulling the cover off.

Standard rotation, notice the impeller points to the right.






Reverse rotation, impeller points to the left.

Drive systems with a single serpentine belt require a reverse direction wp because it moves all components. The older systems use a v-belt or multi-ribbed belt that was designed to drive a single accessory, therefore all belts would turn the same direction. If your buddies system is designed as a single belt "serpentine" set up then it most likely will require a reverse rotation wp. hope that helps

That's because you don't have a "serpentine" ("snake-like") belt.

You have a flat, wide, ribbed belt, of the same design as the ones used later in serpentine systems.

Flat, wide and ribbed, is not necessarily the same as "serpentine" (winding in and out among the accessories).

The 86 (and up through 87 & 88, in MCs) system uses a clockwise rotating water pump. The water pump does not care whether the belt is flat, wide and ribbed, or V-shaped, narrow and smooth. All it cares about it which direction it's being driven. Which is clockwise, in the case of the non-serpentine systems.

Serpentine systems drive the WP with the back side (smooth side) of the belt, which makes that pump turn counter-clockwise.

Sofaking nailed it there. Also, the impellers will fool you as to their rotation. Most people think the impellers scoop the water and pushes it thru but its really creating a kind of vaccum and pulling water along.