Rick,

I know little about your c10 rear end. Where is this gap...it must be between the precision bearing you got from NAPA and some fit on your truck. Maybe the bearing to housing fit, or the bearing to axle fit. Is it safe to assume the bearing is perfect and that it's the proper one for the axle, but that some component on your truck is worn.

How and where are you measuring this "gap". Maybe your test method is giving you false readings. :confused:

Stuart