On my 57 Bird with a 312 it's doing the normal "getting pretty warm while idling in traffic" . I flushed the coolant system, put on a 6 blade fan, installed Casco's modified water pump, used the big thermostat and choked down the by pass hose but nothing helped at all. As long as I'm moving it runs at normal temp. Before I spend the big bucks on a big radiator I've heard of people back flushing the coolant system. How do you do this? Any help would be appreciated. Thank's, Lex