I found a couple of 7/16 x 14 bolts. The ones in the rods would be 7/16 x 20 but, I couldn't find a matching pair of those. One grade 8 and the other SHCS, both the same length.
Regarding head bearing area, the G8 is .580, while the SHCS is .640 or 10% more bearing area. The head thickness for the G8 is .290 and the SHCS is only .187 at the bottom of the hex drive area. OA height is .437 so, that won't be as strong. The corner radii, under the head, looks about the same but, less than 1/64 on both. The socket is 3/8" and the corners of the socket are .429 so, the socket, itself won't add much to the head strength above the root of the thread.