Engine size has nothing to do with the funfactor diff cups breaking. I am still running the stock motor. I broke a diff cup just driving across a football practice field the local high school uses. The stock diff cups are made really bad. The magnum diff cups are much better I hear. Do yourself a favor and do the diff cup mod. You can try it, maybe you will have better luck than me. But when they break, we will be here to help you mod them.