Clone
Red Plate 5.0 to 5.5 either pipe
Green Plate 7.0 to 7.7 depending on header size used
Purple Plate 8.9 to 9.8 depending on header size used
Blue Plate 9.6 to 10.5 depending on header size used & stage of engine
Unrestricted 12.7 to 13.5 Stage 3 with large header (deduct 1hp for mini pipe)
Unrestricted 13.9 to 14.30 CE Edition with large header (deduct 1.2 hp for mini pipe)
B&S Flathead
WKA Purple .425 Plate 5.2 to 6.0 hp
Blue IKF .425 5.7 to 6.3 hp
WKA Turquiose .500 7.2 to 7.8 hp
IKF Red .500 Plate 8.0 to 8.5
WKA Gold .575 9.2 to 9.8
Unrestricted 11.5 to 12.1
B&S Animal
WKA Purple 7.0 to 7.5 hp
WKA Blue 8.2 to 8.8 hp
WKA Gold .505 9.6 to 10.2 hp
Gold 3 Hole .312 11.2 to 11.7 hp
Black Plate (size escapes me) approx 13hp
Unrestricted Stock 15.7 to 16.3 hp