Mercury - SC1000 Tach/Speed Kit 80 MPH Speedometer & 7K Tachometer Dual Engine Black Face 79-8M0185919. Overview. The Mercury SC1000 Tach/Speed Kit (79-8M0185919) is a complete SmartCraft gauge package built for dual-engine setups. It includes an 80 MPH SC1000 speedometer and two 7000 RPM SC1000 tachometers, both with black faces, white markings, and glass lenses for a clean, factory finish. Designed for twin-engine boats, it delivers precise speed and RPM data right from your SmartCraft system