What do need for a Posi rearend?..Trac Loc

Well,the topic pretty much sums it up.My car came with a non posi highway gear.
While it is cool to keep up with everyone on the highway,I would prefer to step up with about a 3:73 gear.
So with my rear tire and wheel size it will probably be run like a 3:55
gear.So besides a ring and pinion what else will I need to get?

Edited by GoldFinger - 06-April-2016 at 1:47PM

Thanks!
How many splines?
Don't know much about what to buy or look for.

yes that's what i did! probably the best way to go (with new carrier and bearings and seals) then you know it's good! also a good time to replace the axle bearings while it's apart
 you probably have a 28 spline in there now, you could pull an axle and count the splines before you buy! it should be either 28 or 31 splines.
 the place i got mine from doesn't have any at this time. but this is the closest i found new:
 
http://www.ebay.com/itm/9-Ford-28-Spline-Posi-Unit-Trac-Lok-9-Inch-NEW/221873451647?_trksid=p2047675.c100040.m2060&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D35934%26meid%3D9e04a2052be44a74b01ec1f82ef38f09%26pid%3D100040%26rk%3D1%26rkt%3D4%26sd%3D221873451647


Edited by californiajohnny - 06-April-2016 at 5:20PM

yeah you'll need to buy some 31 spine axles