It wasn't an F53 tank, but the concept may help. I once broke 4 out of 6 studs off while removing a fuel pump after dropping the tank. My fix was to cut and grind everything down smooth, and then drill and tap new holes just to the side of the originals, slightly rotating the pump. I threaded stainless steel machine screws into the holes from the inside, liberally coated with Loctite red, creating new studs. I used double nuts on the outside screw threads to snug them in place before installing the new pump and gasket. The replacement pump is still working fine about 10 years later.
