Agreed, the over-fill is probably not the reason it's leaking, just that the more oil made it more obvious.
As to my comments about earlier B/RB engines having a 6 qt oil change, this changed for the 1965 Chryslers V-8s, apparently. When I looked at the AMA specs for the 1959 Diodge Police Special car with its 383 4bbl V-8, it noted the crankcase capacity was 5 qts + filter, just like a normal 1964 Chrysler 383. I suspect the 1965 cars had similar-depth/configuration oil pans as the earlier ones, so might it be that the later ones could tolerate a 6 qt oil change too? Just that crankcase windage would "kick out" that first quart quickly, leaving the pan with 4 quarts in it? FWIW
Running any engine just long enough "for the water to get hot" can be bad, especially in colder times of the year. Once the coolant gets up to thermostat-open temperature, there can be other areas of the engine which are not there yet, NOT to forget the automatic transmission fluid, too. So residual condensate moisture is not fully evaporated, which can also result in bad things not being cooked out of the oil sufficiently for best outcomes. Hence, the old "10 Mile Trip" orientation between "short trips" and normal operation. "Normal" being trips longer than 10 miles/starting event. And, of course, the engine needs to run long enough for the battery to regain a full charge.
Do investigate where the oil leak is coming from. It could be a failing oil pressure sending unit, an oil pan gasket which is allowing oil to wick out of it, or from an aged rear main seal. So, you might get some spray brake cleaner and clean off the gasket areas and then watch for leaks. Then following the leak to its origination point.
Just some thoughts,
CBODY67
).
