You need to measure both the crank hole I.D. and the O.D. of the converter hub, very little clearances(.008 to maybe .015) are needed, no slop allowed If it has a lot of clearance you can have a bushing made to slip on the converter hub to get it back to factory specs.
The crank hub aligns and holds the converter and centers it so it won't wipe out the front pump bushing and seal It needs to be correct, not loose