destro :
cd14, for your 4850 CF did you have to purchase anything special to mount the waterblock? or Did it ship with everything you needed?
What blocks are you using? Supposedly the mounting for the 3800s and 4800s are compatible, but...when I installed my MCW60-R GPU blocks, I had to use my 2900 adapter kit. It matched perfectly. Perhaps I'm missing a bracket that was inlcuded with the block; I will take a look. Are you going with the MCW60-R blocks? In my opinion, they're decent. Had them for six months or so, with no problems. They keep my 4850s in 40s while loaded.
Swiftech MCW60-A2900 ATI 2900 Adapter Kit
Swiftech MC14 BGA Memory Heatkink Kit
Swiftech MCW60-R ATI 2900 GPU Blocks