Speed Odometer Question
Thread Starter
Pro
Joined: Feb 2007
Posts: 548
Likes: 1
From: Victoria VA
Speed Odometer Question
So a while back I went from a 3.08 rear to a 3.70 and the speed odometer was off by about 10 mph. I changer the drive gear inside the trans and got it closer. Now when the speed odometer read 60 mph my gps says 57 mph. I have a red driven gear which is 21 teeth is there anyone that can tell me what gear I can get to get it right on or closer if I can?
Thanks
Thanks
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Willcox has a chart in their help section. 3 MPH is not outside of any limits- I'd rather have the speedo read a little slow than fast. And FWIW: most all GPS units are accurate to within 10-20 feet anyway, so that could be some of your error. get on the highway with a stopwatch- 60 MPH mile marker to mile marker.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Tim,
You are 100 percent correct. Below is the Delco Calibration Chart for the 68-77 cars.
MPH Test
Machine-------Speedo
15 -------------14-18
45 ------------- 44-47
90 ------------- 89-93
In most cases the margin for error is 3 - 5 +/-
See what GPS has done to us....
Willcox
You are 100 percent correct. Below is the Delco Calibration Chart for the 68-77 cars.
MPH Test
Machine-------Speedo
15 -------------14-18
45 ------------- 44-47
90 ------------- 89-93
In most cases the margin for error is 3 - 5 +/-
See what GPS has done to us....
Willcox
