Your overheating problem has the typical signs of a failed water pump. On our cars, the factory pump has a plastic impeller that tends to crack and break apart with age. Some younger than others. The main defining point is that the heater is cold, showing that it is not just a thermostat that is stuck shut.
The water pump is driven off the cam on the transmission side of the engine. pull the cover off the front valve cover and you can see it clearly. It helps to remove the battery for access.
Some of the aftermarket pumps come with a metal impeller and seem to be the preferred replacement. The newest engineering level of the factory pumps seem to have an improved plastic, but a metal one would probably be better.
I suggest you do a search about the water pump and you can come up with a lot more information. I think there may also be some information in the FAQ section.
Congratulations on your SVT.
