Groves on the block above crankshaft.

I'm learning as I go with everything I do. I have got an old junk motor that seemed to be in the best shape I could fine. I'm gonna have the bottom end built by a shop more than likely. As I was moving the block I've noticed these like grooves where the crank would rotate and I was wondering if they was supposed to be there? They look almost too perfect to be something the crank would had done itself, I think it might have been manufactured like this. I have picture of almost all cylinders you can see the difference in them. The grooves are near the walls of the cylinders. In one picture you can see a clear image of the deep groove in it. I plan on taking it to the shop to get it looked at, but I figured I get a little help from some people who know what their doing before wasting the money. I have pictures of the crank if needed.

Images: https://imgur.com/a/CLmNg