Need help with install

that looks to be a cross flow radiator, from the sounds of things your concern is running to cold?,, if so replace the thermostat or make sure it is working, these radiators cool very well, you may need to step up the thermostat to a hotter range.......any chance the engine over heated ? causing you to install this radiator? if so you may want to look into a related reason for the stalling from the overheating. just guessing on this