I am trying to figure out what gears i have my car in 5th gear and running 60 is at 2000rpm and at 72 is 2500rpm. any body have a clue?

 

Sounds like a high 2. Something or a 3.08. Easiest way to tell is take the cover off, count the teeth on the pinion, then count them on the ring gear and divide the pinion count into the ring gear count. You can also jack the car up in the air, spin the tire one full rotation and note how many times your driveshaft spins but it isn't as accurate, it will get you in the ballpark though

 

If I remember right my car does 2500 at 75mph with 3.73sand a 26in tall tire

 

Yup...,373's

 

Yeah I'm thinking wrong, that ratio sounds better

 

my rear tire is a 275/40/17

 

i know my last car would run around 100-110mph in 4th (4.6L) with 3.55 gears and this one will do somewhere around 80-90mph in 4th also my speedo is like 8mph off at 55