Gear ratio question

Well, this is not rocket science. There ARE online calculators, but---

easiest way is to beg or borrow a GPS

Measure the tires all the way around, then do some math

Figuring the TRUE rear ratio is easy, first---do you know if you have a limited slip rear? If not jack up ONE rear tire, front tires blocked, put the car in neutral Can you turn one tire? If so, turn the tire TWO turns, and count the driveshaft

If you cannot turn the single tire, you have limited slip. So now, jack up BOTH rear tires, and turn one of 'em JUST ONE turn, and count the driveshaft


According to this:

http://www.race-cars.net/calculators/mph_calculator.html

3500RPM, 28" tire, 3.91 rear is 75 mph

According to that same calculator, you would indeed have a 4.56 gear

According to this:

http://www.gordon-glasgow.org/tirecalc.html

your tire size is indeed 28" (27.99)