There should be no argument with his thoughts. Easier if he can get the fuel injection lines with the used head as well. The old lines do not fit the same. Depends a little on cost though.

I would do it at the drop of a hat if the original #14 head was on the engine. I imagine you would not be doing this unlesss you want to keep the car. A lot better than the constant concern of when the old head might crack. It may never but odds are it very well might as well.

Others will mention if the prechambers have to be modified at all. I just cannot remember. Overall a real upgrade to the 603 engine of your vintage in my opinion.