Even if you don't drop the multiplier, setting the FSB to 333 should be doable. I would suggest read one of the many c2d overclocking guides that are out there. Just so you know what your getting into. Then maybe post up your system specs and ask something specific.
Ran your ram at 1:1 (@400 default) and if not strong from riase fsb, loosen timing ram to 5-5-5-20, also raise voltage ddr2 to 1.9-2.0v
Disabled all feature (eist/speedsteep, c12, spread spectrum), pcie at 100.