aeromotive belt driven off of the fan pully. the universal bracket fits a couple cover bolts with some minor massaging, and a little quick machining of the threaded part the fan screws to and you are set. makes all the press and volume you could even need and isnt too expensive.
from the aeromotive site:
Availble as a kit (P/N 17140) includes: Pump, Bracket and Pump Pulley.
I ran an AirDog and Raptor combo last year. Used the Raptor to adjust my pressures where I needed them. I saw no difference at all in the way the truck ran from 40-60 psi. I think if your anywhere in that range you are fine. Unsure of what I will run next year. Probably gonna take a couple units. Maybe 2 of our new 180/240 units @60 psi.