I just got done putting a flex fan and a 2 core aluminum radiator with 1" tubes in my Eagle Wagon today. I will post some pictures and results after I'm done with military duty this weekend. I had to do a little more modifying to get it to fit than some have suggested. I had to space the radiator about 3/4" towards the engine because of the evaporator for the A/C. After that, it was the usual, measure, drill, install. It took about 2-3 hours to do, mostly from fitting the fan. I went for the flex fan because my clutch has been on it's last leg for a few months now, and last week, it dropped to it's knees and started letting the engine get a little too warm. When I took it off, the seal had fallen off on the water pump side and showed me that there were only 3 ball bearings left! I used a 2" flex fan spacer, but would have preferred a 1-3/4" or 1-1/2". The fan I used was a Hayden 6-blade 16-3/4" part number 3567, meant for 4.1L and below, but is only about 1/2" smaller than our stock fans and has a more aggressive pitch, plus the aluminum radiator should allow adequate cooling.
What I did notice was the noise from the fan in the front of the engine was reduced, new clutch probably would have cured this as well, and there was quite a bit of a difference in power. It seemed that a bit of drag on the engine was taken away, and it was quite noticeable. I'll try to get some mpg figures from this weekend to see if it was affected in any way.