After getting some machine work done, I found this washer in a box of parts that the machine shop gave back to me. The washer fits perfectly on the end of the crank. Can anyone confirm that this is the correct spot for it? Thanks!

 

That looks like a crush washer from one of the block plugs.

 

yeah I think you are right. It fits pretty well around the bolt that plugs the hole in the front of the block.

 

Thats the one I was talking about. Its a crush washer (like the one on your oil pan), really should be replaced.