Green or Newer Coolant Type for Rebuild

I am thinking ahead of what type of coolant to run once I get my 340/420 back in the car this Spring. The engine was completely cleaned, and my radiator and intake were cleaned out too and sitting dry. I will be using new radiator hoses, and then the only other pieces are the heater core/hoses that may have some green antifreeze still inside.

Is there a good reason to blow out the heater core lines and try and run a different style of radiator coolant besides the green, or keep the 50/50 green?
This is a streetcar in the Midwest.

Thanks