Thanks for the reply, you confirmed what I thought about the first 6, they are for the leaf spring bracket.
The second picture is my mystery, they came off the car, I have cleaned them and put them in the tray but I cant remember where they went. I have not mixed the bolts up with any other cars here, I am sure of this because here in England everything is metric !
The second pic seems to show a self tapping type of bolt. I am totally puzzled ! Even more so because I have already restored them so they go somewhere.
Thanks for the note about repro J nuts, I have 5 of the original ones in good condition but one that broke when I was undoing the bolts, I might try to get another GM one rather than risk a new soft one.
The bolts in the top pic look worse in the pic than in real life, the threads are all great and I am going to blast and tumble them then bung them in the Parkerizing dip and they will live again.
Paul.