Highest flowing CFM electric fan that ACTUALLY fits?

There's nothing as annoying as constantly watching the temperature gauge....
Add to that I'm adding a lot more horsepower and air conditioning and I'm gonna need more air flow.

I tried the big Ford 2 speed fan that a lot here use, but no matter how much I offset it to the side I could not get it to clear the water pump.

So, what is the highest CFM flowing electric fan that ACTUALLY fits?

Spare no cost...lol
Thanks

Jeff