Panic posted on the thread we have here (somewhere) about these engines to speak to a maximum practical size for 4 cylinder without a counter balance system. I think he said it was about 2 liters. I'm sure rpm is a huge factor as the older engines didn't turn nearly as high as we strive for now. That said there are some screaming 4 bangers out there. I am beginning to think I chose the wrong cam for what I really want my engine to do. It's not a racer.
