I already have the M90 with the 2.49" pulley. My question was is Roush saying that it is safe for all 4.6L 3V motors to put out 550hp without any other supporting mods? If so, then I won't worry as much when I have mine tuned at the local shop in the next couple months. I have emailed Roush to ask them these questions, but they have not gotten back with me yet.
First, telling stkjock to "FO" is cute, better have said worse to him. He takes internet bullying very seriously. This is only because he has an itchy "BAN HAMMER" finger. You'd do well to be humble and accept flamed guidance for what it is. Kicking around a dead subject isn't terrible if you can accept that some people are going to crucify you for it. But in particular, it's in your benefit not to sass the mods.
Second, regarding the dead subject, there are many topics that have been discussed in great length and detail. The forum search function is your best friend on this forum. Absolute crap tons of specs, data, and builds can be found by using the search function. Teach yourself how to use it, it will come in handy more often than not.
Last, don't believe half of what your read on the internet. Believe even half of that when interpreting what a Vendor advertises. The debate on how much power a stock 3v motor will endure is critically based on tune, fuel, type of power adder, and its purpose (drag, drift, corners, or street). Whether or not it is safe is always debatable. The ability to make the power, is usually without question. Just because you have a M90 with a 2.49 pulley does not make you "safe" for stock internal durability.
I suggest you start with this thread and search from there:
http://www.s197forum.com/forum/showthread.php?t=29199&highlight=stock+motor