3 Valver?
Havent tried this yet. Ive gotten to where I just break them all off and use the special tool to get them out. Im quicker at pulling the old part out with the tool then farting around with the stuck plug, trying not to break it.
If its the three valve Id get the removal tool from lisle and then tackle it on a saturday after Wf. First trip on them kind of sucks but after the first one itll go quicker.
http://www.tooldiscounter.com/ItemDisplay.cfm?lookup=LIS65600&source=froogle&kw=LIS65600
And if its not a 3 valve just go to town on it. Havent pulled threads out on one yet. Done a bunch of them. The only ones Ive had to put inserts in had plugs blow out on them randomly.