Plugging smog holes in heads....

Dartnut said
As cheap and dirty as it sounds, i just used a mig welder to seal mine shut with a quick plug weld.
No leaks, and i was done in under 10 minutes for both heads..........

which is fine if you have a welder available
but if you need to go out and buy the stuff, a tap and setscrews are a lot cheaper then a migwelder