Honestly I suggest an upgrade!
I redid my entire system ~2005.
After everything was replaced & working new would've only been couple hundred more.
It worked flawlessly and cooled well for many many years still regret decision to rebuild vs. upgrade.
The new systems are much better imho and you lose the ginormous heater box under hood as a bonus.
over on fsjnetwork there is a member that sells AC stuff and is very knowledgeable might wanna ask his opinion too?