I wanted to see which speedometer is correct for my Valiant. When I purchased the car it had a 120 MPH speedo in it. At higher speeds such as freeway, the speedo would read 85ish but GPS would show I was going 70. The factory differential had 2.73 gears and the correct speedo drive gear. Since then I have an 8.25 rear with 3.55 gears and have the correct 36 tooth red seedo gear. It seems to still have the same amount of offset at higher gears. To the point, I recently purchased a parts cluster and it had a 100 MPH cluster in it, I did not know they had another speedo other than the 120 MPH. Could it be that it originally had a 100 MPH cluster or does that not matter since the drive gear determines the speed of the cable and thus the MPH on the gauge. The lower speeds don't look to far off but side by side 85 MPH on the 120 gauge looks pretty close to the 70 MPH position on the 100 gauge. Thoughts?