Just ordered a set of replacement bearings for my 9N differential. These are the same for 8N also. I found a reasonable vendor called Locate Ball Bearings when I restored my 48 8N where I bought a Timkin roller 3984 and cone 3920 at $22.34 and $12.54 respectively. Seems like everyone else wanted around $60 for the set.

Today I looked on the site and the Timken roller was $43. They also had that number in a Bower for $14.95. I went back just to check the number on the bearings that I had taken out of the 8N (I saved them) and I was pleased to see that they were actually Bower units. So I ordered 2 each of the Bower 3984 parts for a total about $45 including tax and shipping.

I have used Bower bearings for a long time. No complaints!! Every bit as good as Timken, in my opinion. Keep them greased and will last a long time.