This is the ESC, only get the 100A because it is the most reliable out of all other versions. I have been using for about one year now without any problems.
http://hobbyking.com/hobbyking/store...idProduct=8993
And are you sure you have a Blitz? The smallest spur gear is at 77T.
Here is a video of mine.
[youtube]http://www.youtube.com/watch?v=C5yNtFhXQXQ[/youtube]