Runs then dies

Yote said
Timing (30’) BTC set at operating temperature
900 RPM, vacuum advance disconnected and
capped. Air cleaner off , choke open.

Well that's way off, although I don't think its related to the issue.
Plymouth shows TDC at 900 for manual trans and TDC to 2.5* BTDC at 750 rpm for automatic.
That works OK only when using the original distributors.
For midlly hot rodded, even with factory cam, with low compression, 12 - 16 BTDC at 700 rpm would be a good starting point.

Yote said
0 ohms primary, hot

If accurate that's a problem. Should show a over an ohm. Not all multimeters will be sensitive enough but 0 is a short.
From '72 Plymouth FSM

Yote said
Carb rebuilt by major rebuilder 2900 miles ago.
They rebuild for Summit.

That means nothing. Even if they did a wondeerful job, that was 2900 miles ago. Shavings, dirt, varnish, or charcoal all could have developed or moved around until they block a passage.

Yote said
Fuel was sprayed into carb to confirm no fuel
starvation.

Not a great test and a good way to get hurt. I'd go with that conclusion for now but keep in mind it could be wrong. The checks I listed above are relatively safe and will get closer to the source of the problem.

Yote said
Charcoal canister lines are filtered.

I wouldn't count on that. The canister has filters from when? 1972? and then depending on how the system is set up, when the charcoal has broken down it can make its way to the carb. Worst is if the bowls have vent direct to the cannister. If its open when the engine is running, charcoal dust migrates. Service manual doesn't show a shutoff when the engine is running... I wouldnt write off that possibility.

example Vapor canister filter
rebuilding Charcoal Canister?

My previous post pretty much sums up how I'd approach the problem. There's only three things the engine needs to run; fuel air mix, spark, compression. Divide and conquer.
Good luck.