steve58

My speedo is off by 8 or 9 miles per hour. Speedo says 65 but radar says 56 or 57mph,, previous owner said he thinks it has 3.73's,, any way to tell for sure?

badlx87

Do the old Jack up the rear test. Check driveshaft and tire revolutions, simple way to check gear ratio.

steve58

So i complete shaft revolution = 3.73 wheel revolution?

AdderMk2

other way around. the shaft goes faster than the tires

nitrous_bob

^^^^ yes adder is correct

use chalk if you want... easy to count. mark the DS and like the bottom of the tire at 6 o' clock. wherever you can see it easy. 10 mph is typical for a 2 gearset swap, but they might have partially corrected it.

if they did not correct at all... i would bet you have 3.55's

fyi '89 trans is a 7t drive so correct accordingly

Shelty

yeah kid, leave the car stock for a while, get used to the way it drives and the handling. you jump on the speed parts too quickly your asking for a date with the wall.

even stock, these cars can get away from you.

just clean it up and get familiar with it

steve58

X2,, especially if the Trac-Loc is working properly!

steve58

I did the "jack the rear up" test, and counted just shy of 3.75 drive shaft revolutions to one tire revolution. So looks like I probably do have 3.73 gears,, except I'm not sure about how the correction thing works.