proper way to set index when changing speedometer gear

i have to change the pinion gear for speedometer of 904 trans because of changing tire height, how do i set the index or whatever its called that the gear sits in on side of trans, i think there is certain position i have to have it in. thanks

The tech archives are our friend. http://www.moparts.org/Tech/Archive/auto/21.html

thanks it looks pretty straight forward