I overclocked my Quadra 700 with a socketed 64 MHz oscillator:



The hard part was desoldering the ground pin... but otherwise it's a fairly easy procedure.

I tried slower oscillators also, for the fun of it: down to 40 MHz is OK; 32 MHz starts having video issues... 24.576 MHz or lower, no boot at all xx(

...but I no longer have the 68040 on it; it currently runs on a PPC601 accelerator card on the PDS, which gets the 64 MHz speed as a bonus