[torqjunki]

I had similar results and this is what I did. First I purchased a cheap manual style temp guage kit from local auto parts store. I hooked it up on the crossover near the autometer sensor. The spikes I was seeing with the electric auto meter guage was not seen on the other guage. I pulled the autometer sensor and used a different type of sealant on the threads. This took care of the spikes. It was still trying to over heat during moderate speeds. I have the 4 core alum radiator as well. If I done it again, I would go with the 2 core. To make the 4 core work, you need to get the 7 blade flex a lite flex fan or a stock 7 blade flex fan. The stock ones are hard to find. I believe the part number was 1818. It is very very quiet and pulls lots of air. I think the fan clutch set up stops pulling air too soon and free wheels before the car gets enough frontal air to properly cool. This is what worked for me. If you look at the flex a lite web site, it specifically says that this fan is designed for the four core radiators. I personally like the clutch arrangement, but with this car and radiator it does not work well enough. I could likely add some sort of air deflector in the front, but like the look as is. Good luck.