I have a 30 coupe and when I bought it it didn't have the 12 bolts in the floorboards. Can anybody tell me what size they are? I know they have a cup under the head but what is the size and length of the bolt? The head in the picture looks like an oval head. Thanks.
They're flathead machine screws with dished washers and fit into the D-nuts in the body. Correct and complete sets, with washers, are readily available from A parts suppliers for a reasonable price.
I agree with Ray. If I remember correctly they are a slightly different size than the common sizes from the hardware store and you will ruin all of your D nuts if you use the wrong size.