Remove the undercoating and see how extensive the damage is. A friend of mine is an old school bodyman who can fab the repair. I have a 78 Datsun Z that he replaced sections of the floor pan on. The repair is hardly noticeable after he hit it with seam sealer and paint. See how long a trip it would be to bring it down here.

I also have a late 84 SD that I've been scalping parts from that may be for sale. It depends on whether I cut the back panel out to fix my 85.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.