I know there is probably no easy way to overclock a Power Mac 5500 or 6500 and one may be require to tinker with transistors on the logic board. But, anyone know of anyway to overclock these Macs, either by software or hardware?

Yes there is a way to clock-chip your 6500! I clocked my 6500 fom 225 to 275 and saw a 20% increase in speed! All I did was resolder some resistors on the mother board! see http://violet.berkeley.edu/~schrier/mhz.html for links to the modification.

It seems like you need to be an engineer or an electrician to understand how to use those pages. Did you overclocked the ratio number or the bus speed? Are you able to increase the bus speed at all?

I just changed the pll ratio, I have been thinking about changing the crystal to 55mhz but I have not touched the 6500 since I got my sawtooth.