How much can we overclocked Core 2 Quad Q6600 2.4GHz with it's standard cooler?

Pc Spec:

Processor : Intel Core 2 Quad Q6600 2.4GHz
Motherboard : Gigabyte X38-DS5
Memory : Corsair XMS 2 6400 DDR2 (2GB)
Graphic Card : Gigabyte 8800GTS 320MB DDR3 320BIT
Harddisk : Maxtor 320GB SATA 2
Rom-Drive : Asus 20X DVDRW +/- SATA
Casing : Cooler Master CM690
Power Supply : Cooler Master Extreme Power 600W