1955 K&O Mercury Mark 55 Variants
1955 Mercury Mark 55 Top: Gen 1, Gen 2 and Gen 3
1955 Mercury - Gen 1 - top: Small notch just behind faceplate and top-mount screws in cowl front and back - rarest 1955 Mercury
1955 Mercury - Gen 2 - top: Small notch just behind faceplate and no top-mount screws
1955 Mercury - Gen 3 - top: No notch - smooth cowl just behind faceplate, no top-mount screws in cowl front and back
1955 Mercury Mark 55 Port: Gen 1, Gen 2 and Gen 3
1955 Mercury - Gen 1 - Port: Small notch just behind faceplate, no screw in rear cowl wrap, and no oil hole - rarest 1955 Mercury
1955 Mercury - Gen 2 - Port: Small notch just behind faceplate, screw in rear cowl wrap, and no oil hole
1955 Mercury - Gen 3 - Port: No small notch - smooth cowl just behind faceplate, screw in rear cowl wrap, and oil hole in mid-section