Top end rebuild, tuning issues

[SchreinerM]

Recently pulled the top end of the engine. Cracked heads, so the guy at the machine shop put some together for me (not Vortec heads).

Summary - 350/350, new heads, cleaned-up stock intake, rebuilt q-jet, HEI, new plugs gapped at .040", idle adjustment screws ~1.5 turns out, checked and rechecked firing order, pulled and plugged vacuum advance.

After learning my way through timing, it fires up. Using a timing light I'm showing ~30 degrees advance at 1,200 RPM. I let it warm up idling until the choke plate opens then...

Let out the idle adjustment screw - engine dies. If I tune back the advance (aiming for 4-8 per the Chevy manual) - engine dies. If I try to drop it in gear - engine dies.

What am I doing wrong. Is it possible the balancer is off relative to the timing marks?

Thanks in advance,
Matt