does any one know what the hole is in the engin block . it is located under the mounting bolt on top of th egine it looks to me like a breather but it goes through the block k to the bottem case . if you have the block of off the frame you can look down between the two mounting brackets wich are part of the block it self woudlent water get in it here . any help?

 

It is for the tach. Once upon a time these engines resided on motorcycles. They just didn't change the castings I guess. Don't worry about it. If there was an issue with it then I am sure that it would have been changed YEARS ago!