Yes. You can definitely join top engineering colleges even being an IB student as there is nothing to do with IB program and these engineering colleges. To get admission in top engineering colleges you need to qualify the qualifying exam with good score.

You will be allowed to sit in the engineering qualifying exams and even if your final IB grades will not be declared then also you will get admission based on predicted IB score and on provisional basis. The only requirement for IB students would be that they should have studied Chemistry, Physics and Mathematics as main subjects with a score of 60% in the final exam.