[Rooster in a Coupe]

I know I need Tstats to increase temperature and slow the flow rate as suggested above.
I'm thinking 77yrs of crud build up causing restriction of flow in radiator and no Tstats to restrict water return to radiator, between these two I'm getting a head of water building in the top tank and what can't get through the radiator takes the next way out which is the overflow
Still open to suggestion, but at this stage going to pull the radiator, install Tstats and new hoses when parts and time permit

Rooster
PS. Its a very original car