Plugging smog holes on 302 heads

What i've done before is to run a 1/4'' drill bit through the holes, tap them with a 1/4''X20 tap, and then run a standard 1/4'' bolt in the hole, and then grind them off flush with the exhaust manifold surface. I used red loctite on the threads.
It worked well for me, the set screw idea would be easier though come to think of it.