If you still have the intake off, lay some aluminum foil under each of the holes coated with wheel bearing grease while "SLOWLY" drilling the holes. Discard the foil carefully keeping the shards in the grease. Use a pencil magnet to pick up any possible escapees. Put down more aluminum foil and then coat the tap with grease, which will keep most, if not all of the shards in the tap. Again use the pencil magnet to make sure the are none left. Put some heavy shop rags under the holes and rinse the holes lightly with a solvent. Put RED Loctite on the Helicoils and slowly screw the in. Let the Loctite cure for at least 3 hours before reinstalling the intake. I know this is very time consuming, but it works. I've done it many times on cast iron and aluminum heads with great success. As I said, use the pencil magnet all around the area many, many times just in case a shard or two escaped.
