OE and Aftermarket Stock and Performance Parts for the Briggs Model 28 Flathead. We commonly find these as race engines for S/P and G/P Racing Mowers. We have lead the way for performance parts and have advanced mower racing to new levels of speed and competition. 284700 is the most common model number for the Briggs Model 28 Flathead check your owners manual for model, type and code before ordering.