Yes[strike], easily![/strike] I've overclocked my i5-3570K to [strike]4.2[/strike]
4.0 GHz using the stock cooler
EDIT: Slight correction. I think I actually got to around 4.0 GHz with the stock cooler. But since I've used another cooler (the Cooler Master Hyper 212 EVO), then I got to 4.2 GHz with no problem.
Sorry about that!
But, just check core temperatures using
Core Temp while doing any stress testing. And ensure core temperatures do not exceed around 80°C.