Help with differential ID, please.

[krayzog]

I am about to order a bunch of parts, to rebuild my differential. I just want to make sure I have what I think I have. Any help will be appreciated.

My truck is a '61 C10 SWB, 327, 3 speed (on the floor now). It originally had an I-6, on the column. I know the engine/trans has been swapped, because my dad and grandpaw did it when I was a little kid (with me over their shoulder, on the creeper... in the way). I know I have a 10 bolt, non-posi, but, is it original or is it another swap that may have happened while I was learning to color in the lines and play well with others?

Also, I counted the ring teeth, divided by the pinion teeth and came up with 3.33. I've had 7,000 chevy trucks (maybe a slight exageration) and I've never heard of that ratio, did I do something wrong?

There have been other mysteries about this truck that I have yet to uncover, like...exactly what transmission it has (doesn't fit any of the sideplate diagrams I've found)...why the starter just decides not to work 1 out of every 4 times...and why the truck seems to HATE MY TOOLS!

I've been lurking for a while, and enjoying every minute of it, but this is my first real post. Again, any help would be awesome!