which electric fan? 1960 with 350

[Samz]

I have a 1960 Chevy with a 350 in it (only had 402 miles on the engine and trans when I got her). It already has an electric fan, but I think I may need one that cools better. I recently got this truck and it has a newly rebuilt 350 and a newly rebuilt 400 trans. The truck is pretty solid and drives really nice. I'm going to hook up the AC soon, but I want to make sure I have a good fan in there before I do (these Arizona summers get pretty dang hot). The fan that's in there now is new, but the guy didn't know what CFM it pulls. He told me that I should probably get a better fan. The guy was very honest with me and he is an old gear head that knows what he's doing. He did a great job on this truck.

So, if any of you can suggest what electric fan I should consider, please let me know. The fan in there now is about 16X16X2 1/2. I have just under 3 inches to spare in thickness for the fan. Also, the fan in there now does not have a shroud. Thank you in advance.