In all actuality I have already done most of the things you listed as well! When I built the 360 and put it in I removed a massive amount of wiring to make it look cleaner in there, carpet was removed a long time ago due to rot and it was now green and no longer red LOL. Heater box is still there to help evacuate heat from the engine. Spare tire holder was never there when my dad got the truck 20 years ago, must've been removed by previous owner. Same as well with anything loose and not using. I tend to remove the tailgate when I do any racing for aerodynamic reasons so there's maybe 50-75 pounds? Or more? I have no clue what that would weigh. Somewhat close but not perfectly exact to what you have done. Sounds more and more like the scale gave off a false reading
