just curious, i have a 9 bolt with 2.77 gears ( originally 3.45, but they were changed for some reason?) anyways i get the onw wheel wonder. i went to the track not knowing it wasnt working and ran a 15.291 @ 90.77 mph. something has to be wrong. btw the 60 footer was 2.364.

 

If you are getting wheel spin, a posi will reduce the wheel spin--which will help your 1/4 mile time. How much it will help depends on how much wheel spin you have without the posi, and how much wheel spin you have after you add the posi. Adding posi to a deep geared car(like 3.73) usually helps more than a high geared car, since wheel spin becomes more of a problem with better gears. Also, if your tires are crap and won't grip, adding posi won't help much.