Marcus exams are possibly the best you can find for free and if you got that score, in my opinion you need to study more.
Again in my opinion,
you should aim to get around 85% in his mock exams if you want to be sure of passing.
I'm sure that Marcus has a list of links to mock exams. We have a list here of mock exams. It's at:
http://www.javaranch.com/mock.html
