Do you have to run a gasket on the water neck on a chevy 350 in order for the thermostat to function properly? Or can you just rtv it. I just put a thermostat in my 79 and down chevy 350 stock intake manifold and stock thermostat housing/waterneck. i put the thermostat in spring down into the manifold. It seems like the thermostat is open all the time.