Since you have to drop the tank anyway, just replace it. Your original tank is over 50 years old and is bound to have rust and corrosion inside. A new fuel tank is not expensive. I just bought a new tank for my '72 convertible off eBay for $133 shipped. This is the tank I bought:
https://www.ebay.com/itm/295734796177
While you have the tank out, replace the rubber fuel supply and vapor return hoses and the associated hose clamps. Replace the rubber hose and clamps at the fuel pump inlet, too. I also recommend replacing the vapor return valve and its rubber seal (about $55 from NPD). It might also be a good idea to replace the fuel gauge sending unit. It's probably a rusty mess as well, plus the filter "sock" may have disintegrated. They don't cost much, usually less than $30.
As they say, "Buy once, cry once." Replace it all now and you'll never have to do it again for the rest of your life. The whole job will take one afternoon and cost you less than $250, and when you're finished you'll have a million dollars' worth of peace of mind.
I am about to do this entire job on my Mustang. I am waiting on parts to arrive and for my helper to have some free time. We did this exact same job on my '73 F100 Explorer Special a couple of months ago as well. Its fuel tank was a horribly rusted mess, as was the sending unit. The rubber hoses were leaking fuel, too. They weren't cracked. The fuel was literally seeping through the 51 year old rubber! I shot this photo of the inside of the tank with my cell phone camera. You can see the rust and crud, as well as the fragments of the broken fuel inlet filter "sock".
