There is a 757 panel and a A330 panel that come with a fmc.  But, you will be disappointed as they are limited.  They can only do route data from the fs flight planer and other functions are limited as well.  A more functional fmc is included in the fs9 upgrade of the fanda groups dash 8 300 by Oleksiy Frolov. Do a search of different file libraries and you can find it.  You will also find in the docs links to the fanda site which has everything you need for that plane. Very systems oriented.  Other than that an fmc will cost you some money but when you consider the cost of a full motion professional sim session versus the cost of an add-on that is just as systems detailed it's worth it.