Update. I couldn't find any carriage bolts small enough, so I did weld in the heads of some #10 machine screws, then chucked the screw into a drill and use a bench grinder to bring it into the shape of the original rivet heads. I then finished them smooth on some 220 sand paper while still in the cordless drill.
Carl

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission