David, thank you for the info. I was using the Astro rivnut tool today in a tight spot and could have use the tool from Pegasus. Time to order this tool.
The fuel tank is located in the center of the car directly above the radiator and heater coolant lines. Insulation is needed to keep the radiant heat from frying the occupants. I lined the bottom of the fuel tank with Sticky Shield from Heatshield Products and covered the radiator and heater lines with heat-dissipating sleeving (fiberglass sleeve covered with silicone rubber from McMaster Carr).