freeze plug / coolant leak question 72 dart 318

The original owner of my car knew he had a small leak in the radiator. He had installed what I call a "weak system" radiator cap ( 7 lbs ) . He had also added Barsleak from time to time over several years. That worked. I drove the car home ( 2854 miles ) without a problem.
First order of business was a new radiator and proper 18 lbs cap, and recovery reservoir.
About 6 months later I found one plug leaking behind the starter. See how system pressure reveals weak points ?
I went under, dropped the starter, poked a screw driver through that plug and peeled it out. Then I very easily poked that screw driver through the nearest plug forward. I knew they were all the same age, same rusted, sooo, I replaced every plug I could access short of pulling the engine. Yes the passengers side plugs were just as weak.
I flushed and flushed, cleaned large chunks of barleak out too. I know I'll need to pull the engine someday but... over 7 years now with no recurrence. Good luck to both of us.