If I were to drain all the coolant from the engine, how much does it hold? I'm thinking about trying some Evans NPG+ to see how it works. I have used it before with great results.

 

I remember seeing a total coolant capacity amount in the SVT brochure that came with the truck. I don't remember exactly what it was, but it did include the radiator, tanks, and intercooler, so you might want to look in there.