since nobody beside Bill answered, lets do a little resurrectiion
Yes, it can easily be done.
You will need to buy
* good barbs
* waterblocks with 775 mounting brackets thou. But you can maybe source them cheaply as EOL or stock cleanup. And if push comes to shove you can use a drill bit to "adapt" an existing AM2 or 1150 bracket to 775.
* Radiator is as Bill said 2x 120.3, but different combinations will work.. check what is in the "bargain bin", but if you want to go crazy then Koolance offers a rack-mountable solution
And since you have access to it:
* Eheim 9/12 or 12/16 hose
* Pump : You can probably get away with one Eheim Universal 1200 (the famous 1250 which has been used in PC Watercooling for decades), but you probably can get away with 1048 also. Another option would be a submersible 600
* one or two manifolds - i think they exists for aquarium setups , but if needed can be sourced in plumbing or gardening section of local DIY store
* reservoir/container.. even a Tupperware box will do if needed, especially if you go for the submerged pump route.
* various bits & bobs from the Eheim collection, like quick releases & shut-off taps
* a power-brick to allow you to switch on the pump(s) before switching on the PCs