5.9L Magnum build with questions

What is the purpose of the coolant lines?
They are supposed to circulate the coolant from the back of the heads so it doesn’t deadhead at the back of the heads. It’s an effort to promote better cooling in an endurance application. This isn’t a drag racing engine rather a road race type build that will see 20 minute track sessions. There’s a lot of different opinions on them, but I always wanted to try them.