AC upgrade on 73 Sport

MoparMike1974 said
AC components should be sized to each other for optimal performance. Although it may work with mismatched components, it will work better with the correct parts.
The newer evaporators and heater cores are much more dense than the old ones. They have smaller passages and 2-3x the fins.

If the system uses a TXV (thermal expansion valve) the sizing is not nearly so critical. You need to learn to charge with superheat/ subcooling readings and just be careful when you charge it, monitor things. I admit this can be difficult without a huge fan to provide "fake highway airflow."

I bet it would work fine