Trawling through the many hundreds of reference photos of original 3.0RS and RSR cars I've saved over the years, an item that restorers seem to have little regard for is the gauges, they're all over the place and vary greatly from car to car!
Of course the majority of these cars have been raced, modified, crashed, rebuilt and re-shelled over the years with little left original.....when taking the cars back to their former glory it seems that whatever is easiest to hand will suffice! It makes referencing a little tricky!
As always it's the largely original road cars that provide the best insights.....
With the introduction of the G-Series the gauges moved away from the earlier silver button instruments and the good news for me was that little appeared to have changed from 74/75 to the 77 Carrera 3.0 and a couple of my originals were fit for purpose. Apart from the fact that the vehicle had been stored terribly and the gauges suffered accordingly

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...the exceptions in my case being the clock not being required (although some RS cars do have them) and the fitment of a 300KPH/180MPH speedo - Gary Cook kindly helping me with a practically NOS original speedo for my build.
The other noticable difference, standard on the RSR and a common upgrade on the RS, was the addition of a 10K rev counter. In 1974 a G-series 10K gauge wasn't available and therefore an earlier silver button gauge was used. I was lucky to acquire a 10/73 dated original 10K gauge perfect for my needs.
A bit of TLC all round and I have the perfect period correct set

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....or so I thought!
This should have been a perfect set, and would be with a regular fuel tank, however what I hadn't taken on board was my upgrade to a 110 litre fuel tank! I'm pretty sure this would have also meant swapping out for a different fuel gauge!.....I'll cope with what I have for now and this can be something for another day!
Cheers,