Overheating Problem - '97 Cobra

Air in the cooling system would be my guess

These cars are known to have head cooling issues. Can you determine if it had the coolant crossover fixed? Mine does not I believe however it does have an upgraded rad to keep it cooler. It's not my DD but I still see the temps climb higher than I would like to during normal driving even.

Start with air in the system - common if not bled correctly post-repair.

Let it cool down to ice cold.
Jack up the front of the car (you're creating a high spot for the air).
open the degas bottle
remove the bleeder fitting on the coolant crossover (in front of intake manifold black pipe, uses 1/4" ratchet extension)

fill the degas bottle to the recommended cold line, start engine. run heat at full blast.
watch bleeder provision - when fluid starts to come out, cap it.
do the same with the degas bottle, or if engine comes up to operating temp and heat works, fill it to hot line and cap it.
let jack out, take for test drive, repeat if necessary. sometimes you will get a random pocket in one of the heater core lines or lower hose with all those bends so if repeat is necessary, squeeze hoses a lot during warm up phase.

while you're in there, do the obvious other checks - fans coming on, leaks, etc?