Name that RPM

[yvan]

I suspect that my tach is telling little white lies. From your experienced ears what RPM is my 6V71 singing at?

http://youtu.be/GBmz74_fpy0

[HB of CJ]

Best memory and guess here is between 800 and 850.  Just a guess.  HB of CJ (old coot)

[luvrbus]

650 to 700

[yvan]

Thanks , tach reads 1300 on fast idle and 800 in this video. http://youtu.be/nEQpC3dxY_g

[Lin]

You can get an optical tachometer cheaply.  Once you know the correct RPM, you can either re-calibrate your instrument or get one that can be adjusted.