IT'S A FLATHEAD, I CANNOT TEL IF IT A VERTICAL OR HORIZONTAL CRANKSHAFT STYLE ENGINE. IF IT'S A HORIZONTAL IT PROBABLY WON'T WORK FOR YOU IN LAWNMOWER RACING. WHAT YOU NEED IS THE FIRST 2 NUMBERS OF THE MODEL NUMBER. IF IT'S A 28 THAT'S AND VERTICAL THAT'S GOOD IF NOT YOU MAY WANT TO SKIP IT AND KEEP LOOKING.