rear end identification

[Silver R/T]

I got this number on my rear end 207042   12  then big 2 on side of it. I know its not sure grip  since one wheel turns opposite way of another one.

[deputycrawford]

Not a sure grip if wheels turn oposite direction. The numbers have my questioning the identification. If the numbers don't have the last zero in there then its a 742 case. The largest straight pinnion of all the cases. The 489 has the largest pinnion but it is tapered. Many consider the 742 to be the strongest case of all.

[Silver R/T]

would this fit my rear end then?
http://cgi.ebay.com/ebaymotors/DANA-Sure-Grip-Mopar-8-3-4-8-75-CLUTCH-Limited-slip_W0QQitemZ7999596609QQihZ019QQcategoryZ33731QQssPageNameZWD1VQQrdZ1QQcmdZViewItem


or this would be better?
http://cgi.ebay.com/ebaymotors/AUBURN-MOPAR-8-75-SURE-GRIP-PLYMOUTH-DODGE_W0QQitemZ300029827978QQihZ020QQcategoryZ33731QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[Runner]

those will fit but i wouildnt waste my money on an auburn unit. the fist one is a nice piece,  id call dr diff and hget one from him.  he lives in polson mt.

[Silver R/T]

but isn't first one for DANA rear ends? It has to be DANA pumpkin to fit? Doesnt look like it'll fit 8 3/4
I already got rear end, so I only need sure grip unit...right?