I'm putting a '77 main fuel tank/skid plate on an earlier frame that doesn't have the 9 nuts welded inside the frame. My searches have only came up with rivet nuts. I also know later Fords used tapered self threading bolts where no weld nuts were present. These were used mostly to secure exhaust hangers to the frame. It seems a skid plate needs a strong anchor to withstand the weight of an EB sitting on a rock. What approach would be the strongest? Are there other ways to do this job?