How do you completely flush engine, radiator, heater coolant on a Slant 6?

Modified idea from 40 years of this.

1 Drain radiator
2 remove block plugs & drain
3 disconnect both heater hoses and flush core with water.
4 connect water hose to a heater hose pipe and rinse block
5 Close radiator drain, remove lower rad hose and block lower hose connection. I use a gloved hand. Fill radiator, remove hand and drain radiator.
6 close all drains, install hoses and block plugs. Fill with water and drive. Drain again and surprise it will not be clear water.