Yes, 1200-1500 cfm seem about right. The radiator manufactures have a series of formulas that they can caculate the specific radiator size to a certain engine size, and moving a 'x' amount of air thru the core will dissipate 'X' amount of heat. We do the same thing on race engines, alot of the stuff we work with either hasn't got water jackets or has a closed system, ie, they're not to be run but for short periods.
Now, its best to have a larger fan on your motor to keep it cool than one not big enough. Your coolant and the time that you leave it in your block to absorb the heat, then its given over to the size of the radiator to dissapate the heat from your coolant to the air via the fan.
Have your system hooked up so that the fan comes on at a low enough temp so that it won't hAVE TO RUN TOO OVERLY LONG TO COOL THE MOTOR DOWN. ALSO, READ BACK A FEW POSTS....THERE WAS SOME GOOD INFO THAT ALL THE GUYS THRew OUT THERE AbOUT HOW TO SET THEM UP AND EVEN THE USE OF MECHANICAL FAns. RON AND TED AND THE OTHERS HAVE ALOT OF GREAT INFO PUT INTO SOME OF THESE POSTS, SO THE SEARCH BUTTON IS TRUELY YOUR FRIEND HERE. THERE'S ALOT OF FOLKS HERE HAVE CONCERNS HERE ABOUT WHAT TEMP. TO HAVE THEIR MOTOR RUNNING AT.
(Sorry. my caps lock is malfunctioning, new keyboard on its way)
For my 2 pecos worth, I run a motor on the cooler side. Now, some of the stock mills of later years ARE DESIGNED to run hotter so the emissions system can help them run cleaner, so if your gonna use a later motor, make sure you have taken some of this into account. Because some of the parts are designed NOT to let the motor cool, but to let it operate within a certain range. Thats why for alot of years you were limited to the range of thermostats you could put into a specific motor.
On your electric fan, they have adjustable thermostats that you can adjust......and as Ron and I believe Ted said, you hook them up a certain way...and they'll run when they shouldn't......
Theres alot to be said for the mechanical fans, they do work, and have pratically no drag. The motors I use them on in the past reved so hard usually they'd come apart but this was on race motors. Anything less that ProStock, you'd be OK.
Whichever you decide to run, always run a fan shroud....it helps with the cooling, and is also a safety feature. While tuning that 2x4 setup, and studying the situation, you'd be suprised where some folks have a tendency to put their hands. I lost the tip of a finger from a blower belt...
Hope this helps...
