If it didn't have the hole in the block there would be something seriously wrong with it without the hole.
The Tecumseh's were well known for the connecting rods breaking because the beam of the rods were made too thin. That was an extremely common problem with the rod breaking.
Eventually Tecumseh made the rods a little bit stronger/improved and there are several Aftermarket companies who still make replacement heavy duty rods for those engines.
Those engines are still very popular, especially with Go-Kart racers and to power Mini-bikes, there are millions of them still around.
I just worked on 2 of the same engines pictured the other day, 1 of them had a broken camshaft and stripped gear teeth. The cam broke right where the gear meets the shaft, another common problem with them.
It has a lot of good parts on it to use for other engines, plus the electric starter, so I swapped out the crank and cam between the 2 and had a good running motor again.