73 duster - gas gauge not working

Im ordering the sending unit now but I wanted to know what you guys thought about getting the larger size fuel line choice.

Mine is the smaller line but I plan on going with larger motor (360) in the future.

Would I run into problems if I got the larger size and then necked it back down until I got the cash up to just redo all the lines bigger?

Or will a 360 run fine on the small lines?