The Speedwell rev counter was a product of John Sprinzel’s company Speedwell Performance Conversions and reputed to be the original electronic rev-counter.
The electronics were designed in-house by Speedwell and incorporated into a gauge manufactured by Weston, a company more known for manufacturing aircraft instrumentation. A variety of gauges were produced from a gauge with a full scale deflection indicating just 4K RPM right through to a 12K gauge with Formula 1 applications.
Speedwell also produced a rev counter which was essentially a rebadged Smiths instrument which is more commonly available on ebay.
The original Speedwell sales brochure.
Courtesy of Mark Forster, MK1 Performance Conversions.
