warm heat

[junior83]

96 monte z/34 3.4 i've replaced heater core and thermostat,temp goes to 170 and that's it,if i let it sit runnin it will climb to 205,and as soon as you drive it drops back down,has 195 thermostat,i have primary fan disconnected and radiator is completely blocked off with cardboard.i live in ohio and drive 22 miles to work,check radiator as soon as i get to work with digital gauge it reads 200,but car does not get hot inside.warm only,what is causing this.