A/C Question? After Market System

I just tore out the whole factory AC heater system from my 67 Dart GT. I was wandering if it was easier to just put the heater system back in and add the after market AC later OR do the whole thing? Could it be a expense I could put off for now? Thanks for the help.
Happy Thanksgiving!
I added AC to my 68 Barracuda using a Classic Auto Air system. The instructions were good, the parts fit fine, the AC works great. With Classic Auto Air you re use the OE dash heater/ vent/ temp control unit, with some modifications. The advantage of a new unit is the modern AC components, compressor, condenser,, are more efficient than the 50 year old parts. most likely your OE compressor needs new seals and your OE hoses and dryer needs to be replaced anyway.
One thing to keep in mind is the Classic Auto Air unit is made for cars that did not have factory AC, I believe the firewalls in the AC and non AC cars are different. The dash heater/ vent/ temp control unit may also be different between AC and non AC cars. For the firewall difference I have seen postings on the internet where folks came up with a work around. Classic Auto Air could give you the best guidance on fitting their unit to an OE AC car.