I'm not an engineer either, but there really have been some interesting as hell developments over the century. I half bet the biggest reason we've gotten as far as we have today is due to better manufacturing techniques allowing for tighter tolerances in components. That kind of precision has not only brought us more power, but more reliability and longer lasting parts as well. When you combine that with the fact that engines are an ass-ton more complex than when they first came about, that's actually pretty impressive. I think what might be a decent sign that we're starting to hit our peak is the resurgence of turbos in everyday commuter cars. Even mild forced induction is a great way to get more power out of an engine. I've shared it a few times before, but if you haven't seen it, check out some of the classic reviews on Motorweek's Youtube Channel. In the mid '80s, turbos were a pretty popular way to get extra power out of engines that were really the best of what manufacturers had at the time.