I too am a little confused by your description of the problem, which threads are stripped? The ones on top? Maybe you could post a picture for us?
The case/motor that you are working on does not normally need case savers or time certs, it is the toughest case ever produced by Porsche for a 911. It's easily capable of handling the stress and heat of turbo motors putting out 500+hp, so the 180hp SC never wears it out.
