What kind of cooling do I need for overclocking my eVGA TI4200?

[godspeedx]

I'm planning on overclocking my eVGA GeForce TI4200. I have an all aluminum case with 4 80mm fans. Do I need any different fan for the vid card?
Here are some pictures of my vid. card

Thanks.

 

[randomboy]

I'm at 275/510 with the stock HSF and havent had a problem yet....