105 at idle or while moving?
First, ensure the system is FULL. Some can take several attempts to completely fill. Breach upper hose cold to verify. The radiator sits lower than ideal in Cobras.
If just at idle, do you have a proper fan shroud? A proper shroud will utilize the entire surface area of the radiator. Also, make sure your electric fan has good cfm at 0.7"-1.0". (fans published numbers are at 0.0"). The full info should be available on their website.
Good luck
Gordon Levy 520 494-2745 in Maricopa, about 25 miles from Chandler, may be your best resource.