Where can i Find one?

 

found this, dont know if that is what your looking for.

http://store.summitracing.com/partde...5&autoview=sku

 

Most tuning devices, Xcal and others will allow for tire size recalibration on 99 and later trucks. You can also change the size of the vss driven gear on the trans - 10 min job, $ 12 or so, a calculator..... the only easy option for a pre 99 truck.
Do a search on vss and tire size, etc.