Tracked one of the rattles in my '62 C10 down to the driver door being out of alignment. Front of the door was in too far and the rear was out too far. Easy fix. LOL!!
Adjusted the hinges so the front came out, but then there was not enough travel in the stricker plate to bring the rear back in. After puzzling it for a while, I looked at the striker plate on the passenger side to compare the setup. Looks like a previous owner had had them off and got them swapped when they put it back together. Ok, this should be an easy swap. Nope!
Passenger side went back together fairly easily, however, the driver side stripped out a couple of the bolt holes on the back plate. I had to tear it back out, fill the holes and drill and tap them.
That solved the problem and once I had all the adjustments done, the old beast sounds a lot better going down the road. Minimal wind whistles and none of the major rattles.
As I solve more big things, the little ones start to show up. You know the kind, you can't hear this rattle because that other one is louder. :-)