Can you pressurize the heads to see if I have a crack or just need a new gasket

If you suspect a failed head gasket you can buy a kit that checks for combustion gasses in the radiator or coolant tank. Here is a link for you. https://www.amazon.com/Lisle-75500-Combustion-Leak-Detector/dp/B0007ZDRUI

*Automotive machine shops* have the equipment necessary to check for cracks in the cylinder heads .. Aluminum heads have to be tested by 'pressurization' - magna-flux doesn't work. It would be well worth the time and money spent to have that done!