I ran across these guys who built a 4 cylinder Briggs & Stratton engine out of 4 one cylinder B&S engines. Kind of looks like an old 4 cylinder motorcycle engine. Petty cool and they are using the small HF mill, a drill press, a welder and a small Atlas Iathe. I would have liked more information on how they made the cam and crankshaft and set up the distributor. The videos are short so there are lots of them. Here is the first one.