My engine temps have been higher than I'd like to see lately. 208 unloaded, A/C on, pulling a mild grade at 60-70 mph. 234 pulling 10-12k, no A/C same grade at 50-55 mph. I pulled the cat and put in a flow-through muffler hoping it would help, but it really didn't. '04.5 HO w/ auto. Are these normal temps? The numbers are from my attitude display, not guesses. Can I lockup the fan clutch? What aftermarket options are there?