Long story but I did not (remember this is a '73 system on a '72) and there is no _need_ for a condenser. What is the long story of your problem? I have spent a lot of time on this one and now get it. Listen to @MaxPF as well.
You're using the original condenser? Is it serpentine, or tube and fin? What are the pressures? I'm just amazed, because I haven't seen many R-134a retros using the stock tube and fin condensers that worked that well and didn't have sky-high discharge pressure.