Type R Club of America

Does anyone know where I can find a bolt that holds the upper portion of the rear seat belts? Perhaps a size? I noticed that the previous owner put the wrong size bolts, they are too small.

For anyone that is interested in replacing the upper anchor bolt for the rear seat belts. What you need is 7/16-20(thread) and 1.5" in length. I was able to get zinc coated ones at Home Depot and a set of 7/16 washers for about $6.