QUOTE(Chris H. @ May 1 2016, 12:33 PM)
You won't really need to use those luckily.
I took a set and mig welded the top end (hex) closed, makes for a quick, down and dirty smog hole plug, that also hold the smog tins in place.
Those would blast up fine for that purpose.
Ran an engine for years like that, sold the engine now in a bug and I know it's still running.