You may want to check out Speed O Motive in covina. They actually won a contest on the 408 stroker they build. A buddy of mine has had some good success with them.
I spoke with Superior today and after some tap dancing they convinced me to bring it in for an autopsy. They also asked if I could pull the engine for them because they are so busy. I am going to pull the engine send it in and see what we get. At this point I am willing to pay for parts but think the labor to rebuild should be covered. Stay tuned.