Mercury - SC1000 Speed Kit 80 MPH Speedometer & 7K Tachometer Dual Engine Gray Face 79-8M0185906. Overview. The Mercury SC1000 Speed Kit (79-8M0185906) is a complete SmartCraft gauge package built for dual-engine boats. This kit includes an 80 MPH SC1000 speedometer and two 7000 RPM SC1000 tachometers, both featuring gray faces, white numerals, and glass lenses for a sharp, modern finish. It's designed for twin-engine Mercury SmartCraft setups and delivers smooth, accurate performance data right