A lot of it depends on the block you're talking about. You need to specify since the lifespan seems to be all over the place.
We've seen crazy blocks like the supras and vipers take in mad boost and still live a long and healthy life.
Its all about finding the weakest link and making it "above par, and then some".
Thats the downside of tuning - you really have to anticipate the next thing thats going to break.
My buddy blew the 2nd gearset in his VW. Hes pushing 300+ CHP in a car designed for 110. Strange things happen when you push the limit.
