Buick 225 Water Pump Pulley ?

I am working on getting my 225 together in my 3B frame. As I go through my parts and planning out my work, I noticed that I have two water pump pulleys.

1. Single 6.5" with number 1359065 stamped on the pulley.
2. Double 5.5" with number 1380956 stamped on the pulley.

Both pulleys line up with the outer belt valley on the double pulley on the crank. The double water pump pulley lines up on the valley nearest the water pump.

The question I have is which pulley should I use? They both appear to work with my 4 blade fan, but do I want the water pump turning faster with the 5.5" pulley or slower with the 6.5" pulley?

My inner crank pulley valley will be running my power steering pump, while the outer crank pulley valley will be running the water pump and alternator. If I use the double water pump pulley, I don't see that anything will be in the outer valley of the double water pump pulley.

Thanks

RVS

 

I don't know which pulley you should use. I use a single as that is what my engine had on it.

I know some people use the double water pump pulley and a double alternator pulley attached to a 3 crank pulley. It is obviously overkill unless your running on board air, and or encountering belt slip. It is cool to have three belts.

 

You have pictures of how the belts are ran?

 

I don't as I am puting it back together. The crank is a double. PS pump goes on rear (nearest engine) crank valley, while the water pump and alternator go on the front.

Hope this helps.