Brain Drain

What’s the best way to flush a cooling system at home? In my case, I’m not talking a system that looks like a chocolate shake, just something that’s been neglected in recent years. Engine is a stock ’77 440 in my ’73 Satellite wagon. I installed petcocks in the block per your advice when I swapped the engine in.

For my money: Chemicals. The 2‑part flush/neutralizer, then drain and totally and refill.