Front end Chassis Issue, 97 Ford Super Duty

When all else fails. Check for worn U joints. That chassis probably has a 2 part drive line since you noted that the center bearing had been replaced. Also check the drive line halves where they make up for timing marks. Some are marked, some are not. If marked the idea is to assemble the drive line with the marks matched.
If there are no marks try assembling the drive lines 180 degrees from where they are presently assembled. If this is the problem you may have to change the driveline around a couple of times to smooth things out.