Originally Posted by ronjenx

The reason I asked is I spelled out in a previous thread of Rattler's exactly how to tell which gears are installed without taking anything apart.

Originally Posted by ronjenx

If you want to know for sure, and remove all doubt, do this:

Chock the right rear tire, fore and aft.
Put the transmission in neutral.
Emergency brake off.
Jack the left rear tire off the ground.
Put a jack stand under the frame, just in case the jack fails (had to add this).
Put an index mark on the aft end of the drive shaft, visible from the left rear wheel.
Put an index mark on the left rear tire at the 6 o'clock position.
Rotate the left rear tire 2 complete revolutions while counting how many times the index mark on the drive shaft passes its original position.
That number will be your axle ratio.
Remove jackstand and lower jack.
Put transmission in gear and/or apply emergency brake.
Remove chocks.

If the driveshaft turned slightly more than 5 turns, they must be 5.13's

Originally Posted by Leave Town

I have the auto with 35's and I just had 5.13's put in. I also did the Hypertech just as soon as I came back from the gear shop. I drove it 400 miles today and it runs really well. Almost like stock.

I have no trouble, and mine runs 2500 Rpm at 75MPH. I try to keep the rev's up to about 2200 or so on the freeway otherwise it will kick down out of overdrive when you pull a hill...

Hope this helps.