I'm sure u did this, but I'll ask anyway. Is the seal retainer flush with the back of the block? Maybe there is a misalignment issue. Last one I did, I put the seal & retainer in with no crank & checked to see how the parting lines lined up.
Did this. No crank in block, seals in, everything was nice and round. Parting lines almost not detectable by finger. Did this twice actually. Thanks, J.Rob