Symbol Parameter TO-220 TO-3 Unit
RthJC Thermal resistance junction-case 3 2 °C/W
RthJA Thermal resistance junction-ambient 50 35 °C/W
So get the TO-3 one. With the one in the link is a TO-220 package, it is impossible to use the TO-220 packaged one for what you want.
Even that with 12 volts going down to 5V you are dropping 12 - 5 =7V. At 2A that is equal to 14W. So to keep the junction temperature below 100C assuming a 20C ambient you can only have an 80C rise in junction temperature. At 2 degrees per watt and 14 watts you are going to get 2 * 14 = 28C rise.