The shroud-less fan chaotically moves a lot of air around under the video card. At the default 44% fan speed it seems to do the trick on my MCW60'ed 480s. The heatsink plate was somewhere in the lowish 40s when measured with an ir gun. I was concerned at first, but seeing those readings while folding for 48 hours @ 1.138v put my fears to rest.

$65 of used blocks to drop a combined 100 degrees Celsius at load. Best cooling upgrade ever.