alexandervdr

I made a spreadsheet once, these are the tables for two rear end ratios, given standard size wheels/tires. Given some errors in rpm and speed gauges it could be one of both
I measure my diff years ago by measuring 1 turn of the back wheels and check the corresponding number of turns of the drive axle.

AZDoug

Its not wrong at all.

70/60 x his 2500 RPM observed tach reading at 60 MPH should give 2916 RPM tach reading at 70 MPH.

We don't know his transmission driven gear is correct. We don't know if his tach is correct, or if his speedo head is on the money

I was merely using his reading to come to possible conclusion of what gear set he based on what we were given.

And given the unknowns, it could be either one of the two I mentioned.

I would actually say it is probably 3.36 just because that ratio is more common than 3.08. We can rule out 3.5 and above.



Doug