This is a replacement spring perch for the front of a GM Dana 60 that has become bent or rusted out.  Made from A36 plate. At 1/4'' thick it has a little more beef than the factory piece.  This will match the height of the casting on the pass side.  Height on this perch is 5/8'' taller than most perches on the market.  So if you need just that little bit more in the back,  you can buy a pair.  These are sold individually.