Motorcycle Repair: Spark Plug Threads, intake leak, o ring

Question
A friend of mine has a 1970 FLH. When I did the motor for him I found that the previous owner had Heli-coiled the spark plugs.I wasn't too confident with its condition and the other day my buddy blew the plug and heli-coil out of the head. My question is can these heads be welded and re-drilled or should I just look for another head. Also I put an S&S Super E kit on the bike and found I could use the band type or the O ring type intake seals on these heads, whats up with that?

Answer
When the plug threads are bad in the heads, I drill them and make a steel insert. I have found over the years the heli-coils just dont work. You can attempt to weld them, but its tough to weld a big hole like that.
On the intake. If your heads take the band type then you need a band type intake. If they take the o-ring type then you need a o-ring intake. If you try to interchange then you will probably get a intake leak
Good luck and happy riding
Mike