What kind of horsepower does a stock bottem end take? I'm just wondering if an ~300 horse N/A mustang will run for "ever," in a sense. What HP rating to guys start to lose pistons and rods?
That's a question that I don't believe anyone has a solid answer on. I made 440 rwhp on the stock motor for 9k miles and was fine but I'm sure it couldv'e gone any day too. Obviously the tune is critical but in the case you speak of I think the motor could live a long and happy life.
Tune is extremely important on the 4.6 . You should be able to run 300hp safely for years and years,Ford is doing it with the exact same short block on the new 05 GT with 300hp. The general rule is about 400-425 with a safe tune.