Need Help. What water pump?

Hey Guys. I have an 89 5.0L HO that I'm getting ready to put in the Mav. I have decided to delete my P/S so now I have a question. I want to use a serpentine belt with only the water pump, alt, and crank pulley. What pump do I get? I thought all the water pumps would bolt on the same? But I have 3 different gaskets in the set.

So what I need is an aluminum pump that measures 6" from the face that the pully bolts on, to the back of the pump. I need this in the rotation of the old motors. I want to use my 89 cover too.

Here is a pic of my cover

 

My gasket is the one at the top

 

This is what I want to end up with. Thanks Mavaholic for the pic.

 

Can I use a standard rotation pump on my reverse rotation timing cover? What pump will bolt to this cover?

 

Well I figured it out myself. I'm going to use the original 5.0L pump and run an idler on the driverside. That way if I change my mind on the P/S or when I find a deal on a blower I don't have to change everything back.