300ex how many miles approx to get a rebuit engines

how long the engine last.
is it worth rebuilding it or buy new motor

[Nausty]

I wouldn't go by miles but instead of how many hours and how hard those hours were. I would say its worth it i don't think its that hard and only costs about 100 bucks but if you are lazy and the engine blows then its gonna cost you. Plus i think you get a power gain after getting a new top end.