I can't seem to find a 1st gen vacuum pump for my 5.9 anybody know of any sites online? Or is it possible to use a 2nd gen vacuum and PS pump?? any help would be great

 

You can buy the pumps themselves and replace the bearing in the housing. Its a bit more in depth job but its a pretty straight forward job 2hrs max.
You can use the intercooled or 2nd gen style you'll just need to have a oil line made. I've seen one of the non intercooled versions destroy a timing case.

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I have a second gen pump on mine... used the oil line from a 2nd gen also!!!