You already built that to be clear? Z77 combined with Sandy Bridge is unusual.
You should be able to overclock 4 bins over stock via the Turbo function. So the 2600 with Turbo on runs at 3.5Ghz with all 4 cores active. 3.6Ghz with 3, 3.7Ghz with 2 and 3.8Ghz with only a single core under load. You should be able to increase those values 400Mhz each via the Turbo multiplier.
Leave the BCLK at 100. For everyone saying you can't do it, with Sandy and Ivy i5 and i7 non 'K' processors on overclock capable motherboards you can get the 400Mhz with any of those CPUs. You have to use a P67, Z68, Z75 or Z77 board though.