70-72 vs 73 cooler lines

1st off if you do not know what the radiator is you need to start there.
If factory look for the number on the top tank and there are plenty of search results to look that up.
2nd off you can always make your own.
There are many ways to skin this cat. With the mix matched set up it may be the easiest and best route then trying to be disappointed waiting on parts to only find out they are not correct for your new application. I’d start with the lines for a 318/904 duster or dart. That would get you close if you need to buy new.
Syleng1