318 is not hot enough

So just alittle bit ago I started the duster and sat there with the meat thermometer and waited for the temp to get up to where it operates at and the stat never opened my stock temp gauge was pretty accurate to the meat thermometer it runs about 160 and because of that my 180 stat never opens. So should I replace the stat for a 160 so it fully circulates or restrict the air flow in front of the radiator. Thanks again