ok, so I swapped my gauge cluster from the 85 mph w/ dummy lights to the 115 mph with actual gauges. I replace the coolant temp sensor with one for the gauge and not light. well when I'm driving the sensor will slowly work it's way to topping out at 260 (or atleast that's what I think it is.)

My question is, should I be concerned? is it overheating by being that high?

if it helps any, I have the stock mechanical fan on my car.

 

sure sounds like something is "off" with the guage
(such as wrong sender) Does car smell or act "hot"
when gauge is at 260? If the high temp readings only
occur at higher speeds,check that the air dam is in
place-it is needed for radiator airflow at higher speeds
as clutch fans freewheel at higher RPM and electric fans
generally don't pull enough air to cool at higher speeds
without the airdam.