I have an old Allis-Chalmers b10 garden tractor with a 9hp briggs & stratton cast iron engine. I was looking at replacing it with a new briggs vanguard engine...maybe 16hp or so. When I compare the engine specs, my old one has a 3.5 inch bore and a 3.2inch stroke, where the new 16 hp has a 3 inch bore and 2.6inch stroke.
I know that is it overhead cam/valve and all, but will this deliver the same kind of power that I am used to? That old briggs has been a workhorse, and I don't want to downgrade power/torque..etc. Did something change in horsepower ratings?