Check with McMaster Carr to see if they have the bolts you need.

Another option is Mr G's fasteners in texas. That guy has every kind of automotive fastener ever made. And he has life size pictures on his website to compare.

Mr. G's Enterprises Automotive fasteners, of all types
5613 Elliot Reeder Road
Fort Worth, Texas 76117-6013
817-831-3501 or 817-838-3131
https://mrgusa.com/

1950 Chevrolet 3100 (Ol' Roy)

1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)