I never removed the heads. Did it right on the car. Bring the piston all the way up to the top on that hole. Do your helicoil thing, then vacuum the cylinder out with a strong shop vac and a clear plastic hose (home depot, lowe's, etc) that is small enough to go down the hole and rotate around.
Helicoil site...
http://www.emhart.com/products/helicoil.html
keensert......
http://www.keensert.com/
threaded inserts...
http://www.carrlane.com/catalog/inde...1E173C1B08535A
Tool trucks, like Snapon, Matco, Mac, will have what you need also.
They will sell to the public for cash. Check phone book, or ask you nearest shop for their #.