I've always had the issue of my 69 with a 350 running hot. In the winter I'll stick around 180 on the temp gauge but as soon as it gets warm I'm almost always running at just under 220. In the middle of the summer I rarely drive, or if I do it's at night. I'm too afraid of the car overheating. I'm not sure what thermostat is in the engine right now, but would having a 160 degree thermostat allow me to drive in the summer? I'd prefer the car stay around 180 if possible.