which is better??
 

Should I get a flex fan or a dual fan setup from a junkyard? Which setup works better? I don't have a shroud and am having cooling problems (at idle). I have a four core rad and a tranny cooler.

It seems odd that you have cooling problems with a 4 row rad, maybe you need a lower temp. thermostat, is your water pump ok? What lbs. pressure rad cap are you using? Give the cooling system a thorough going over before you spend $ on any upgrades. Or maybe the system just needs a flush. Just my .02. Keep on truckin':D

I'm not sure about the temp of the thermostat. I run a old school four blade fan and it sits about six inches away from the rad. It also runs constantly. I would like to get a dual fan setup but if a flex fan works just as good i'll go with it. The fluid is new and so is the rad.

Re: which is better??
 

IF YOU CAN GET A SHROUD, THIS WILL MORE THAN LIKELY FIX YOUR COOLING PROBLEM AT IDLE. I TOO HAD THIS PROBLEM AT IDLE WITHOUT A SHROUD. MY PROBLEM WAS THAT I HAVE AN ALUMINUM 2 ROW RADIATOR FROM GRIFFIN AND A STOCK SHROUD WOULD NOT FIT. I BOUGHT A SINGLE ELECTRIC FAN FROM SUMMIT AND A THERMOSTAT TO TURN IT OFF AND ON AND HAVEN'T HAD ANY PROBLEMS SINCE.

Yes, the missing shroud is the problem. The fan can not pull the air through the fan properly, it is just sucking air from where ever.
Your best bet, and probably the most cost effective, would be to get a clutch fan, upgrade to a better fan with 6 or so blades, and install a shroud.The flex fans are hand gernades waiting to explode and rip through your hood and who ever is in it's way.