1 more question what is better to run one big fan or a dual fan set up???

It's best to cover as much area of the radiator as possible.

Even tho Rattruck's statement above it generally true, I would want to make sure that the duals are moving as much air(CFMs) as the single. Most of the larger duals move a boatload of air and are real currnet hogs. Make sure that you design the appropriate relay capacity with a dual. This is the most common problem with the dual setups I have run across.

I also would not mount duals as a pusher type of fan. They are usually shrouded to a certain extent which is good for pullers, but may block enough incoming air at higher cruising speeds. This is not the case with just about most singles even though I have seen "Black Magic" fans mounted as pushers. Not only are these beasts ugly on the front, they will definitely impede air flow at moderate speeds.
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Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

Everything about old cars is personal choice but I prefer 1 belt driven mechanical fan, the bigger the better, and with a good bit of pitch. If you have a small block Chevrolet and are in construction mode,Zip mades a very good raised water riser. It moves the fan up 5 inches or so and has brackets on it fot the alternator and air conditioning compressor.Almost all the people in the 32 club here in SC run this set-up with no problems. My own 32 Roadster has this set-up with a 18 inch 7 blade clutch fan on it. Even if your car is completed, this pump takes very little more space than te standard short pump.Hope this helps.
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Steeldeuce

Randy- does that big of a fan make a lot of noise?
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American by birth....Southern by the grace of god

No ..... it is a clutch fan. going down the highway it freewheels. It is just like the one in a evreyday V8 rear whee drive passenger car. It is temperature controlled. GM has a name for it but the name excapes me. A senior minute I guess.
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Steeldeuce