3:91 complete third member 489 case

mycuda said
489 strongest pinion. But stock cone style suregrip
742 came stock with clutch type sure grip. But smaller pinion shaft

Although the 489 is a 1 7/8 pinion and the 742 is 1 3/4. The 1 3/4 pinion in the 742 has a larger inner pinion bearing for better support.