I have a 427 Crusader in a 1970 Century Resorter. Over the last two winters
two 1 3/4" brass plugs have popped out from under the engine block and were
found sitting in the bilge. Last year I simply pushed them back into place
and the boat ran fine.

Are these so-called "freeze plugs"? Both winters the boat's been winterized
as usual. Should I be concerned about these plugs popping out? Should I do
something to secure them in place so they won't pop out while the boat is
running?

Thanks!