Ok. I did as bill said. I jacked up the left rear tire and left the right side on the ground. Put trans in neutral and marked the tire and drive shaft.
2 complete turns of the rear tire netted just under 4 turns of the drive shaft. That should mean 3.90 gears.
So, either the speedo is more wrong than I thought or the tach isn't completely accurate or both.
I'll have to go out on the highway with the GPS and try to dial in the speed. The tires are 215/75-R15. The website I found says they are 27.7 inches tall.
According to what the gauges show, at 55mph I'm turning 3000rpm. On 27.7 inch tires that calculates to 4.57 gears. With 3.90s, I have to figure out what variable is wrong.
All that being said, I still either need to swap the rear end or get an overdrive trans. I'm having a hell of a time getting a lead on an sm319.
