Only Z77, Z87 and Z97 chipset motherboards allow overclocking. Even though your CPU is overclockable, overclocking CPUs on other boards destroy other component of your motherboard, I advise you to not overclock on this motherboard.
You can reffer to this link :
http://www.asus.com/sg/News/0yYwfwL2ZA9CFAMK
ASUS clearly says:
-The 4th-generation Intel Core K Series (‘Haswell’ and ‘Haswell Refresh’) processors include Core i7 4770K, Core i5 4670K, Core i7-4790Kandi5-4690K. ASUS does not guarantee that later-announced Intel CPUs with overclocking features (‘Haswell Refresh K’ Series) will be overclockable on ASUS H97, H87, B85 and H81 Series motherboards.
-ASUS does not guarantee that Intel new Pentium processorand Core K Series (‘Haswell’ and ‘Haswell Refresh’) processors will be overclockableon ASUS H97, H87, B85 and H81 Series motherboards in the event that Intel issues software and firmware updates that result in function changes.
-Overclocking may affect a system's stability, or even cause damage to the components and devices. Overclocking is always conducted as the user’s own risk and expense. ASUS is not responsible for any damage caused as a result of overclocking.
You better go with a z87 or z97 chipset in your case, they are a bit more expensive but you will be sure that your motherboard and other components of your system will stay safe.
Here's what I recommend you :
http://www.newegg.ca/Product/Product.aspx?Item=N82E16813157372&cm_re=z87-_-13-157-372-_-Product
Or
http://www.newegg.ca/Product/Product.aspx?Item=N82E16813157529&cm_re=z97-_-13-157-529-_-Product