was an 85 housing which is the stronger style. factory spring perch the only thing that was not stock in/on that axle was the shock mounts and the dodge leaf springs. 

the rear axle does have alot of strength issues.. mostly with the housing. they LOVVEEEE to peel and squish and bend.. ive seen it all and ive seen it alot.  ive had less problems with my half ton chevy junk than i did with toyota  axles..

and gearsets dont fail because of housing flex.  they  fail because the ring gear deflects  ( has nothing to do with extra ribs on the housing)  and they murder themselves.   trucks with v6 thirds eat themselves just as often as 4cyl housings.