Hi,

You must be talking back quite a ways. They haven’t put motor oil in metal or cardboard cans since the early eighties at best. I still have a punch in spout.
I use it now to push down the toilet paper roll for my Frantz oil filter canister. I have three cars fitted with them going back to 1974 when they were reasonably popular.

Now how that for talking about the old days.
Good days are according the molecule of cream you are floating on in a tall glass of milk. Some are higher or lower in the same glass.
Even though, the curdled seem to lump up and spoil the whole glass.

A $5 car is unheard of.
That was a project bargain to get into. Today, they say, you haul you get it.
In what year did all of this take place? That bought the owner a couple six packs of cheap beer.

Maybe he was rebuilding the carburetor while still bolted onto the engine?
If it was screw and not a mounting nut.
Fords used studs and nuts.
You would think a small screw would have gotten out by the exhaust valve. But then a nut, that’s another story.
The piston and combustion chamber must have been peppered with dings.
Yep, the spark plug tip probably got smashed.

A hole in a piston is usually from lean burning and bad timing. Also a very hot of heat range on the spark plug being used. In the likelihood of trying to burn off excessive oil and keep the plug cleaner.

Premature Detonation can be confused with a nut knocking around in the engine too.
6 months of running that way was purely fortuitous.

Phil