yea, i understand the difference between the two. im going to call a shop and ask a price quote from them

 

There really is no way around the fact that to do this upgrade and to do it right with new parts is gonna cost you some dough. Remember, you get what you pay for.

 

Check this.

8" third member

 

I'd want to know that it is limited slip/locker and not a spool. You would want to call the rebuilder first to make sure it isn't a spool.

 

The ones you posted from summit are the drop ins for a non locking diff. They replace the spider gears and some require machine work on the carrier to get them to fit. Also the torque capacity of them is somewhat less than a locking carrier. I have an 8" in the Cougar, it doesnt have a posi, but I want one for it. While I rebuild all the rear ends in cars its usually cheaper to get the carrier, and a set of gears and install them in your thrid member/pumpkin.

This is what I am talkin about. The ring gear bolts to it, and you wont have problems with torque capacity. FYI the 3rd and 4th gen F bodys use a similar type of diff, as the one you are looking at, in the stock rear ends. The LS1 can break one in a single day and they are only 300hp. True they are a 7.5" rear, but they break the spider/pinion gears inside the posi. Rebuilt plenty of them things. If you are spinning on something like lose gravel, then one wheel hits pavement and hooks, you just broke the thing. The Highway Patroll cars are always breaking them like that. They also break as the guys come out of the water box and one tire hooks before they let off.

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


This is what my Cougar will get I wont depend on the drop ins to live as long as this thing will.



It usually costs me $700-$1200 to rebuild a rear end, that includes new bearings, seals, gears and differential. To do it right will cost you about the same. Its not worth it to skimp on these parts, they take the most abuse of anything other than the transmission.