Does anyone know the max CFM of our cooling fans?

I had a fan quit on me, stupid fan, and I wanted to upgrade it to something larger. Now, if the CFM is under 2000 for both fans it would be a needed and easy upgrade, but if the CFM is over 2000 I think you'd get into fan-size issues. But I don't know. I know the shroud has dual fans in it, does anyone know the size of those fans??

Thanks all,