A518 Flex Plate Help???

one hole is offset on all flexplates. the flexplate/converter only lines up one way.

Well that's defiantly good to know. But I have tried every possible way and I just can't get the thing to line up with all 4 of the holes on the converter. I think I am going to need a new flex plate anyways though, because I was looking at the converter off my 727 and it was two balance weights between the drain, and the new lockup one I got with the 518 has no weights. Does this mean I will need to get one of those B&M flex plates?? If so, what would be the part number for the one I would need to get? My 340 has a cast crank.