running hot right after starting engine

The engine is a 360 with a big alumin. rad and the engine as soon as you start it is already hot and reading hot in the dash. Is the thermostat no good?

What you're saying is after you crank it for the first time it does not take long for it to get really hot?

If that is the case it could be the thermo sticking or you have a restriction somewhere. Collapsed hose maybe?