bolt holes in buick cranks are not equal spaced purposely because the cranks are external balanced.
the reason for uneven spacing is so there's only one correct way to bolt it up ensuring that the heavy side and light side of flexlate goes where its supposed to
on a forge crank its typical to do internal balance and neutral flexplate , but the bolt pattern doesn't change
you should keep spinning until all holes line up, but on the odd chance someone screwed up a little if your setup is neutral then there's no issue opening hole a little if its off ..but it shouldnt be
what you need to be careful of with forged cranks is the radius edge on the output flange , because of the curved edge you need to radius (bevel cut) the inside edge of the flexplate to ensure it will mate flat to the crank flange .
Appreciate the input. Engine is internally balanced. Tried spinning the flexplate in every possible position, it's not going to work without a little opening of 2 of the holes. Didn't see it being a big deal. Just thought I would ask first.
Ok thanks for the help guys. I have another question with this situation. I'm putting a turbo 400 trans in this car witch I have never done with a turbo Buick before. Will the converter bolt right up to the flywheel? I don't have the converter yet. Just installing the trans for Mock up so I can build the headers.