Same mounting as the 5 and 6 hp Briggs L-head. Mounting base is 3-1/8"x6-3/8", 3-9/16" Bolt Circle on side of engine or 2 9/16" square pattern around the shaft.
Auxiliary PTO shaft is 1/2"Dx1-1/8"L, 1/8" woodruff style key, no tapped hole in end of PTO shaft. This shaft is shorter than the normal 1.5" PTO shaft found on most tillers.