Thats really good for air cooling, just remember to keep your temps under 75c.
After you set your memory clocks in bios do another standard benchmark for 15 minutes to make sure the ram is running properly and no crashes are occurring, if thats good then start the OC process.
The i6700k should OC easily, try running 1.250v and 4.6Ghz on air, if you feel brave you can push it higher. As hunter thought me, if it crashes add o.o5 volts... so 1.255v, ect...
Past 4.5Ghz you won't really see much of a difference other than benchmark scores.
If you need help in the bios on how to set things up just fb msg me. Also be sure to monitor the voltage in cpuid or hwmonitor.