There are two, possibly three (for SS7) multiplier jumpers (BFx). They may be two pins each but most boards have three pin ones. The jumpers will most likely be close to the CPU socket, wildly guessing it's JP9. To make sure, just follow the traces from the CPU socket (Y-33, X-34 & W-35).
Can't do much wrong with trying, too high a multiplier will just prevent boot up, too low you can easily recognize on POST.
Bus speed may be switchable 50/60/66 MHz, usually two three-pin jumpers. They're probably close to the PLL (can't make it out on your shot). Again, nothing to lose, probably set to 66 MHz anyway.
Then there's the voltage problem. It may be just a single jumper (3.3 vs. 2.9 V) or a row of 2x4 or even 2x5, located close to the voltage regulator (JP23?, JP22?). With an old Pentium in place and using a multimeter on the VR you should be able to figure it out.
