Now that you own it, get it out of the elements and make a list.
Pull the carpets & check for rust. Also check under the rear window gasket, jack supports & quarters. Plan on heater core. Vacuum pods will also be bad. I've found that I can change most pods without pulling the dash on an SD, not sure about yours. One very qualified opinion is that rebuilding double diaphragm pods doesn't allow full throw. I just did mine & found 1 bad diaphragm (in double pods) so replaced the bad & will take my chances while I look for a good dash.

Once you have a list, convert to dollars, multiply x2 and decide if you're willing. If willing, make a parts list. You need it running well, with AC then comes paint. Check web prices then give Phil a chance on the entire list. He can get most things and be close enough on price so service is worth it.

Have a competent bodyman come look at it before you get far down the road. What I thought could simply be painted over needs to be stripped. Now I have to decide if I'm willing to learn to strip, find a deal or walk. Datsun Z people would love to find a car in this shape but SDs can be bought in better shape for less than repairing so economics says "find deal, walk or drive as is".

For your next old car purchase, take $500 off for what the PO isn't telling, doesn't know or you don't see. They all look better at 1st glance then the fixin starts. Good job on the straight shift.

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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.