I broke off a stud on my 360 and bought a 90 degree adapter for my drill and drilled it out, don't know if theres enough room to do it with a BB. Drilled out the center and left the threads and then worked out the thread remains very carefully.
There are much better engine builder on than me but it sure sounds like theres a huge opportunity in the heads. Do you have a good head shop in your area?
Hate to say it but I would walk past 5 new challengers to look at the Thunderbolt. Funny thing about new cars, in my book once the new wears off in a year or 2 they get passed by for the next great thing.