Just thinking out loud, but the part about the temp pegging out at 220 before the thermostat opens seems odd. It almost acts like the thermostat is in backwards. The business end of the thermostat has to be toward the motor or you could be getting a long delay before it gets warm enough to open. On the other matter of the air flow, try taking the shroud off. It's a free step and you may get better results. I have heard that a bad shroud is worse than no shroud at all. At highway speeds you should be getting plenty of air flow even without the gravel guard. Another thought I had: Is the mix in your coolant less than 50%?? Too much coolant in the mix can make for warmer temps also. Good luck, Jag

 

I would take it to a radiator shop and have them run a test on the system