I know this is common sense but I think it needs to be said. If you decide to weld the tank yourself, please be certain that in addition to draining the tank completely of gas, that you flush it out at least two times with clear water before you attempt to weld on it. In addition, I would not even attempt to weld in the same vicinity as where you flushed the tank out. After you have flushed the tank, give it at least an hour or so outside where any lingering fumes or vapors can evaporate. You would be surprised how little gas it takes to make a big explosion. No need to injure your body or your car further eh? Good luck.
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1969 Camaro SS 350-383ci./365HP, T-56, 12 bolt, Power Trax Locker, 3.73 gears, 4 whl disc, Deluxe black houndstooth interior, rear window defogger, tilt steering, floor console w/gauge package, center mntd. clock, tachometer