Did you post your SHO info? Don't see it in your posts

Add it to your signature please!
Ok, so while we await responses, MY, mileage, mods, condition of coolant, at a minimum. Thermostat requires tune to fully utilize because you need to change the fan behavior as well. And if you have a non-PP SHO, the option to add engine oil and trans coolers (and their value) has been established. Are you sure there are no air bubbles in the coolant?
This
brochure does mention:
"HEAVY-DUTY COOLING SYSTEM REGULATES EXTREME HEAT. An extra-large, high-volume radiator, engine oil cooler
and transmission fluid cooler work in concert with the police-calibrated fan settings, mesh grille and wide airfl ow openings
to ensure optimal operation in times of pursuit and periods of idling."