Stumbling Slant --what is left??

I am thinking there is something wonky with either the used distributor or how it was installed.
Distributor: mechanical advance stuck or center rotor worn and affecting dwell or other failure like a bad distributor cap or rotor or points set or condenser.
Installation: mis timed or spark plug wires faulty or in the wrong order, these days new does not guarantee good.

Have you tried re installing the old distributor?
90 compression won’t rocket you down the road, but it should run.