Tune up questions

I can tell you this: engine idling; if turn the dist CCW [ to advance the timing ] to about 28-30*, the engine will:
- idle faster [ making more hp ]
- idle smoother
- make more vacuum
- run cooler.

I would do this, re-adjust carb, see if it helps the stalling problem.

Backfiring could be many things: bad coil/ECU, fouled plugs, wiped lobes etc.