fuel pump problem

[fortlonsome]

I have 1963 international backhoe it sat for a while and would not start. I suspected it had some water in the system I cleaned every line and changed the filter drained the tank.Then I got to the fuelpump I pulled the service window off of the side of the pump to drain all the fuel and water.90 percent of the fuel come out the rest stayed in the bottom so I got to lookin and noticed what appeared to be a drain bolt on the bottom of the pump I took it out and drained the remainder of the fuel.Here is the problem the drain bolt will not go back in I pulled the pump off and turned it over so I could get a good look in the bolt hole.The threds have shifted a half of hole over I took a center punch and tried to line it back up but they will not budge I am out of ideas on this?