I tried this at the weekend.
I got a ZM80C-Hp kit - the newer grey one.
I installed it as you said, however i was a little worried to see only 2 mounting holes from block to heatsink, but hopefully it will be ok.
I installed it on a 64mb Geforce 3, one of the actual reference cards, made by nvidia themselves
Im not into gaming much some im not bothered that much by performance, however i had this card spare and wanted to silence it. I get about 8000 in 3dmark 03.
No crashes yet, although i have only stressed it for bout half hour. Current temp is 40deg c on top of heatsink. Il worry when it gets to 60ish?
And i think i have enough left over to do another card if i want to
Thanks for the tip.