housing fitment question
 

Hello!
I tried to put together all the irons and housings of the shortblock and one of the housings went on to the dowel pins with almost no effort, but the other one did not want to slide on. i hit it with a rubber mallet several times and finally it went to its place.
is that normal or is it something wrong with the housing?
i checked the housing for warpage with a long steel ruler and a feeler gauge and it seemed to be fine!
so does anyone know if its okay?