Only runs 40 Degrees advanced

I had a buddy over today that as a retired factory mechanic and used to run a speed shop and has rebuilt hundreds of Mopar‘s. We changed all kinds of settings but nothing helped if you try to dial it down less than 20° advance it dies and will not restart you crank it back up to 35 or so it will start and run good so it’s not to fuel injection Something in the Kam and timing is off no matter what we do. So I’m probably gonna tear the motor apart and try to find it.
I would not tear the engine apart until I tried a different harmonic balancer.
None of this makes any sense, something has slipped and is no longer within it's specification.
IMO all of this points to the timing marks being in the wrong place at the right time.
Good luck