My tusl cannot go over 207mhz fsb wall no matter what is core voltage, cpu, vio voltage and mem. Anyway my cusl can - but higher clocks make really big stress to hdd as pci clocks ran over 50 mhz. Try lowering dma/pio mode for hdd in cmos setup, try higher Vio using jumpers near mem capacitors (short all of them after boot to get >3.9v - in case u short them before system won't boot), try different ram modes and sticks. Frequencies over 200fsb/1300 cpu are "lucky draw" for cB0/cC0 as far as i see it.
Good luck anyway.