You might check out
Upgradeability.com' ">http://www.upgradeability.com/ to see if they have anything to offer you.
I bought a K6-III 380 mhz chip from them for about $36.00 to replace an Intel 233 mhz. I can only squeeze 368 mhz out of that old Soyo board with its 66 mhz bus, but I am still happy with the improvement.
They seem to have some K6-2 upgrades as well, but I don't know much about them. My ordering experience went well, and that old computer is still running great. Guess I can't ask for more than that.
-------------------------