Tom, thank you for posting the pictures of your seat belt installation. My installation for the inside seat belt attachment is slightly different. I placed the attachment point starting at the center of the sheet metal pan in the back seat. Obviously, this pan would hold nothing. So, continuing under the car, the Grade 8 mounting bolt is long enough to engage two 1 1/2 in. wide x 3/16 steel straps that goes back to a Grade 8 bolt that holds the tail pipe up to the frame. If I remember correctly, I increased the size of the frame hole slightly to use 3/8 in. bolts throughout the installation. This was done with a round file. There is also another hole in the frame on the driver side of the car in the frame that is not used and available for the second strap. I did shape the strap slightly to accommodate the torque tube shape in the rear floor pan. Using lock and flat washers were needed, everything was tightened down. Ed