R90S tachometer ratio 2:1?

[gwagoner]

Can anyone confirm if the tachometer ratio is 2:1 or something else?

I have a R60/2 conversion with a 1975 R90S engine and would like to add a tachn. Blue Moon sells tach's for /2 that may work and come in either 2:1 or 4:1

Thank you for the help

[gwagoner]

If anyone is interested, I hear that the ratio is indeed 2:1 from my local airhead instrument restorer.

[kirkpatrick3890]

The stock rear drive on an R90S is a 33/11 and the corresponding tach reads W-1.112.
Not sure where the 2:1 is about that you mention.