While this doesn't specifically address your problem with Chinese repro clocks - it's worth considering: When I picked up my Vintage Speedster (01/09), the Tach was bouncing consistently like a Mexican jumping bean. All I was hearing from everyone was replace the "innerds" at either North Hollywood or Palo Alto Speedo shops.
Not wanting to endure that extra expense and downtime, I had my Germany Porsche and VW trained mechanic look it over. His answer: The wiring looked like a bowl of Chinese Bird's Nest Soup without the broth. Kirk's "wirer" musta been badly hungover on everyone of the units going out VS's doors. Anyway, my mechanic rewired the instruments (like, even, properly grounding!), and I've NEVER had a problem since (now almost 7,000 miles later). That's a long-winded suggestion that you have someone check out the wiring BEFORE spending any big bucks on replacing your Chinese gauges or their guts.
