my '89 GT has 3.55 gears and with i believe 24" tires (225/50ZR15 tires) and at 60mph it's at 2000rpm. Here's a test, go 60mph in 5th gear and if it accelerates the same as if it were going 30mph in 4th then you have gears. There's a HUGE difference in how the car responds with those gears than my '84 with 3.08 gears (there's also a large horsepower difference, but i can feel where each engine starts to pull and the '84 starts pulling like about 75 or 80).
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previous name: 84stangLX
'84 Mustang 5.0 LX
my LX
'89 Mustang GT
my GT