81266 Universal Car Seat Adapter - Black - Compatible with Driver & Passenger Side - Perfect for Vehicle Seat Replacement & Customization

I ordered two of these seat adapters for my 1966 Mustang Fastback. One came with the holes pre drilled for installation and one did not. I verified that the pre drilled holes lined up with the holes in the seat pan and used that one as a template for the other side. I somehow managed to cross thread the bolts that attach the seat to the adapter. I'm thinking that the threads weren't properly cut to begin with. I re-tapped the holes with a M8x1.25 tap and installed new grade 8 bolts as I wasn't too sure about the bolts that came with the adapter that attaches the seat. Other than the cross threading hiccup and the holes not being pre-drilled in the adapter, I was pretty happy with the outcome.