Briggs and Stratton engine tins. They're not the same!

So I discovered not all 12.5 HP Briggs engines are the same. 😂 the flywheel is taller on this simplicity 5212.5 I'm working on versus this engine supplied by a friend. The extra engine has a real cast iron flywheel the simplicity Briggs has a plastic fan mounted to the flywheel. I'm beating the newer Briggs probably stays cooler. with more fins.