Some people also expect their garage floors to be pristine. Cars with fluid leaks are not allowed. Well, not leaking is not an attribute of a Cobra engine
In fact, it's said that if you have a FE engine and it stops leaking that means it's out of
oil.
So for all but FEs, fixing leaks is another of the tinkerer things to be done on alternating weekends.
This is not necessarily a Cobra issue, but a general attribute of engines from the period. Seals weren't all that great. I remember the valve covers on the 350 in my 73 Chevelle always weeped a little (so the engine always had some oily dirt on it).