I could use some help really quick. I usually fill my cakes with chocolate buttercream, but would really like to try ganache. My problem is that with every filling i've tried that wasn't buttercream based, the filling came out of the sides of the cake. I tried the buttercream dam and that didn't work either. Am I over filling the cakes, or are my cakes to heavy? What would you all suggest to keep the whipped ganache from smushing out of the sides of the cake?

Whip it stiff enough and it won't, it gets very thick!

Make sure that your buttercream dam is very very very stiff!
When putting the filling in, make sure that it is below the top of your buttercream dam.
One thing that I had found that works good is to not put the filling all the way to the edge of your dam, leave a little space, that way when you put your layer on, it has room to squish.

You can also chill the cake for a while before icing it. This allows the cake to settle and will stiffen the filling.
Whipped ganache is a good filling because, as was said earlier, you can whip it to quite a stiff consistency.