Is there anyway I can fix this
 

The previous owner put a coolant heater in my 350 oldsmobile when I went to go put the radiator back in I took off the hose and coated the sprocket with wd40 as it started to come off this happened. Key thing is radiator is good original condition no rust from coolant.

Soldering radiators is a bit of an art form, you may need a professional?
You will find professionals in pretty short supply these days, however.
Looks like it is worth saving.