Chassis / Seat Belt Mount Question

Hi Guys,

I need some advice.

I am trying to be responsible and add seatbelts to my 70 Swinger. I pulled the carpet to install and found that the front outboard passenger mount in the floor has been covered by the floorpan patch panel and bondo.

Using the driver outboard as a guide, I chipped away the bondo in that area and drilled a small hole in the patch panel to see if the threaded hole is there. I couldn't find it.

Assuming it is gone, what are my options? Do I just weld some sort of nut or something in there to allow me to attach the seat belt? If I did that, would the seat belt even work properly in a collision?

So much for being responsible!

Any help or advice would be appreciated.

Thanks,

Pete