It appears that International Speedometer & Car Radio Sales and Service replaced the MGB GT tachometer on April 12, 1976. This is I think the 3rd time that the tachometer has had service…. in 9 years. This might explain the extra tachometer that I have in the parts bin. Good old Smiths instruments.
The tach needs work again once I get the car running as it flops all over the place. Oh well, just one of the cool things about owning an old MGB.