83, I believe is an extrenal type pump... so replacing it is not too bad. B&M makes a good external pump. And as for the fuel line, just about any braided fuel line will do a good job for ya.
As for the overflow neck (the piece that the overflow hose attaches to is what I am assuming you mean)... that can be welded back into place, or you could look for a replacement radiator from another Mk II Supra. I would check with a radiator shop about the repair. I did one on a 75 Pontiac Catalina with JB weld once... it worked, but thats not the right way to do it really..
As for the overflow neck (the piece that the overflow hose attaches to is what I am assuming you mean)... that can be welded back into place, or you could look for a replacement radiator from another Mk II Supra. I would check with a radiator shop about the repair. I did one on a 75 Pontiac Catalina with JB weld once... it worked, but thats not the right way to do it really..