Floats? Fuel pumps? Who needs them?
" In addition, on the cast iron block single cylinder Briggs and Stratton and Tecumseh engines, the valve stems are parallel to the cylinder. This means that the valve heads set further away from the piston. And in the cast iron block single cylinder Kohler engines, the valve heads set closer to the piston (valve stems and lifters are angled 4°). Therefore, the other engines can't build up as much compression as Kohler engines can. Plus, they can't flow as much air in and out of the combustion chamber at high RPM or at wide open throttle, like Kohler engines can. "
Ton of info:
But he did say that an OHV engine will have more power than any flat head.
He also explains how to convert some twin vertical engines into horizontal engines.