use it if its good, but I did put a new one in my 68 fury - it is a driveway job - no need to drop the tank.
you do need the grounding clip.
where I had problems was with the new lock ring that came with the new sendo unit. the new one was not as thick as the original one and did not seal well. I used the old lock ring.
somewhere on this board I think I put a picture of the lock ring removal tool I made - basically a piece of PVC pipe with notches cut out that fit the lock ring. drilled a hole all the way thru the side of the pvc pipe to insert a bar or screwdriver so you can turn it. presto.
- saylor