/6 rebuild advice

I appreciate it guys.

The coolant is flashing off somewhere as the oil reservoir at this point still shows good oil / high level but clean so far. The milky film is interesting / thick enough to block out the green coolant, but thin layer. No froth on the valve train / rockers, in sump.... I will look more.

I've got a thermostat in my box of replacement parts.

I am going to take off most of the Emissions equipment and eliminate hoses that aren't needed. Clean up the vacuum hoses. I will check the carburetor bolts.

The rear main leak isn't bad. But if I do price out the parts and its ***$, when is it worth it for a rebuild / replace? I've had my 73 charger 318 for decades. It leaks. As long as its a slow leak I'm good.

I actually bought the car in van nuys / North Hollywood
Well, unless you're a glutton for punishment, the engine needs to come out for a rear main seal. lol So do the math I reckon. If you pull it, that's a lot of work for replacing a seal and putting it back with a lot of unknowns.