Hi,
I would not play around with 2nd hand bolts, apart from being worn and possibly stretched they are usually peened on the end.
You can purchase new bolts from The Filling Station or Garry Wallace if you want the original. I just used store bought modern coach head bolts. They do the same job, and no one has ever noticed. If you do still want to use 2nd bolts let me know, I may be able to help you for just the cost of postage.
Cheers
Ray
Some say "Street is neat". I prefer "1928 is great"
I have documented my 45 years with a 1928 Chev Tourer, from 1973 to 2018, and regulary add other items that I hope are of interest to others. Your comments are most welcome.The story of the Red Chev can be viewed at
http://my28chev.blogspot.com/