My Assault racing heads have a nice fast burn style chamber and like timing. The Vortecs I have tuned like about 12° at the minimum.
You are thinking wrong. The old swirl ports like less timing than Vortecs. About 26-28° is all they need.
Also you likely need to change the shape of your AE tables. Progressively higher values with bigger TPS/MAP delta's. Ease off on the lower values if it is getting rich at slight throttle changes.
Must have gotten really lucky on the LS. I had the Express van with the 0411 run 5.7 dialed in very well. I went from the factory converter to a looser converter. All of a sudden it started lean popping if you smacked it to the floor. I ended up adding both timing and AE to fix it. After it rapped up much quicker.
Even port fuel setups can lean pop. Its not a TBI or Carb only thing.
https://youtu.be/gNyr_Z6Q_ck