2001 SVT Cobra Overheating Issue

Hello,

I recently bought an 01 cobra from a buddy for pretty cheap. Its been sitting for approx 2 years, so I replaced all the fluids and finally started her up. After running for a little bit it began overheating. I reburped and flushed the coolant and still had the same issue, with no change. Replaced the thermostat, water pump, and radiator in that order to no change. Took it to a mechanic to do a head gasket test and block test to both he could not complete because he couldn't run it long enough before it started overheating. For the head gasket test the color out the exhaust was normal until he turned it off. For the block test he couldn't complete it because the coolant reservoir kept overfilling and he had to take out coolant. He thinks it is either a cracked head or gasket leak. Wanted to turn to you guys for your opinions.

Thanks,
Braden