I'm a bit old-school, but just like the older 550/750, they crimp the very outside ends of the through-tube down to a smaller diameter. If you enlarge those ends and upsize the hoses and brass fittings to the same ID, you don't need dual cooling. You will have to redrill/retap the head and pump to do this right. Places like Group K mention this and I know it was done to my first ski 20 years ago.