Can anyone help me identify this? It's the rear that was already on my 56 dodge c3. Serial says 2831489 P and has a giant 9 on the side. Is it a 489 sure grip? From left to right, top to bottom, on the driver's side of the differential it had these numbers: 184 2 A 2831489 P AAP
I think you will find the # is a 2881489 instead of a 2831489. That is about a 1970 ply and dodge rear/ midsize car built for higher weight and medium HP applications. It has the weaker 1 3/4 pinion shaft diameter. Still a good rear but they made heavier duty ones. Good luck.
742 has the smaller pinion with the clutch type sure-grip. 489 has the larger tapered pinion shaft with the inferior cone type sure-grip. Best case scenario is a 489 carrier with the early sure-grip swapped in. Either one is plenty strong enough unless you are planning on high tens with slicks.