weld in disadvantage - you're making an irreversible change to your classic truck.

bolt-in disadvantage - bolts can loosen and must be monitored

You can also state these two aspects as advantages, depending o what your priorities are.

The weld-in may also obliterate your VIN on the frame. I don't know about AD trucks, but that's an issue with my TF, a 57.

regards,
Leon