sure grip for my 8.25

[B5charger]

Guys,
   Looking to maybe put in a sure grip in my 8.25 rear end.  Other than another similar  '71 charger in a bone yard, where else could I fing a sure grip to fit my '71?  (I think I heard somewhere, a pre 1992 dakota with a 8.25 rear end would fit?)  How could I visually tell if a differential is a sure grip or not?

[Nacho-RT74]

SG 8.25 carriers are available new from Mopar

[B5charger]

What would I need for to make it a posi with maybe 3.23 gears???

[femtnmax]

What would I need for to make it a posi with maybe 3.23 gears???

I think kits are available. Would need new ring gear housing that accepts posi parts, could use your old ring and pinion. 
I had a 340 duster with 8.25 rear axle, no posi.  I installed the factory performance leaf springs (extra leaf and different leaf lengths on RH side) and moved the battery into trunk behind RH wheel well.  Would leave two black tracks on the road for straight line acceleration.  I thought it was almost equal to sure-grip unit in that example.  Then swapping to aluminum heads and intake manifol would help too.
I would really suggest installing a 8.75 rear axle, sure-grips are available...I know, would cost $$$

[B5charger]

Thanks femtnmax, I know the 8 3/4 would be by far the best way to go.  Just trying to keep it as original as possible.  Besides, it's only got a 318 so I'm not too worried about the 8 1/4 not handling it.

[alcusswhen]

Ebay has some NOS 70 to 96 27 spline sure grips for around 100$. But you'll need a 1/8th" spacer to use them in your open housing. Until today no one made the spacer for a 8.25 Chrysler rear end. After six months of modifying a Chevy ring gear spacer to use for the same swape with 3:90 gears in my own 73 Charger I decided to make the spacers.
If at least 30 people need them for 60$ each. Summit has arp .990 bolts for around 33$ so you get back 1/16" of thread lost top the spacer with stock bolts. I can be contacted at  {alcusswhen@yahoo.com}