Those'd be stretched aluminum B4 chassis kits.

@ George: You say a lot of things I don't agree with but I leave it at that. To answer your question, no, I do not use flat-spotted balls in my diff. I haven't built a diff with the name Fido since 1994 or so when I bought my first Stealth-equipped car (truck!) and reassembled the diff the way I had received it...which turned out to be false. Since then I've never had a problem with building a Stealth diff, whether it be with chrome steel balls, carbide or ceramic. I've also never been one to crank the slipper down, thereby reducing the chances of a barking diff.

I'll give you an example of how I came upon this realization. When I was in high school and didn't have the money to be able to simply replace parts when they could be used again, I still had a smooth diff because my thrust bearing balls were the only thing I always replaced when I rebuilt a gritty diff. I used a set of carbide balls and 2 sets of rings racing 2 times a week for 9 months at an indoor track but replaced the thrust balls each time the diff got gritty. That was all that *I* needed to get the diff back to being smooth.

You can sleep soundly tonight knowing that the last thing that I need is your help taking care of the most trouble free, smoothest designed, mass produced ball differential on the market. I hope there aren't any Cavemen on the board...