Trying to start rebuilt engine, spitting through carb

1966 Plymouth Valiant 225

Rebuilt engine
Confirmed TDC by watching valves
Plugs in correct firing order
Distributor set 10 BTDC
Petronix kit instead of points

I can start and run the engine with the choke on and high idle.

Once I reduce idle and/or open the choke the engine dies, usually with a spit out of the carb, sometimes flames.

The engine will not idle below 1500 rpm.

This is my first time starting a rebuilt engine by myself so I’m possibly missing something obvious.