While installing the rear main in my 440 yesterday I noticed that the cut out for the curved seal was offset to one side about .070". Then I measured the crank position and it was off center the same way by the same amount. The block is a'77. The retainer fits perfectly and the bolts thread in good.

I read somewhere that this was an issue along the way. Is this common?

EDIT: I looked at some photos online of the rear main area and it seems that many are like this. There is a noticeable difference from side to side.