Rubber expansion plugs

I will never ever use one again after I had one pop out on the highway while driving my 73 Charger (318) ....... Heard a "ka-thump".looked in the rear view mirror to see an object meerily rolling the median and at the same time smelled coolant....... It's amazing how fast it heated up without coolant !
You shoulda had an old 383 or 413; lol, I have seen those in demo-derbys drop their coolant right after the starting gun and survive quite a long time, even seeing one claim the last-car-moving prize. True story but yes I'm kidding.