It may be possible, However, most older CPU's heatsinks don't even have a fan on them. This makes it hard to dissapate the heat generated.
Also, I have a PIII 650MHz that i wanted to blow up just for fun, but i found that the BIOS is so simple it wouldn't allow me to change the FSB, Multiplier, V-core, or anything else i thought of to blow it up.
good luck with it. Be sure to let us know how it comes out. I'd like to hear about your exploits.
Alright, but my heatsink does have a fan...except right now its either burnt out of full of dust. I'm in the process of trying to get it working right now. HAHA, but yes, I will tell you if I get it overclocked.