riverracer au

Trying to help a older club member whose speedo is displaying too high, he said at 110Km/h (68m/h) it's showing 123km/h (76m/h).
(disclaimer: i haven't checked it myself)
He is running 255x50x16 tyres and a 700r4 transmission.
I have jacked the car up and spun the tyre 1 revolution and get 2-3/4 turns of the drive shaft, which points to a std 2.73 diff ratio.
I then pulled the electric speedo sender and there is a 'red" 17 tooth drive gear and a 'green' pyramid shaped 42 tooth driven gear installed.
(Didn't actually count the teeth, just going by the internet saying that's what they are.)



I have plugged all the info into the TCI speedo calculator, and it comes out at 35.9 (36 white) tooth gear should be correct.
But doesn't look like it's available, or will fit/mesh correctly.

What is the std gear set supplied in a factory transmission?
What do we need to change?
Is there a simple fix?

James93LT1

https://www.corvetteactioncenter.com...cle.php?id=584

riverracer au

Thanks for that link,

Looks like then it may have an have had a 3.07 rear originally but has been changed out for a 2.73 and they were too lazy to change to the correct gear.

Guess anything is possible in it's 39 year history, especially now that it's in Australia.

arbee

It would appear that the white gear is available from several places on Ebay.