273 distributor rotor rotates counterclockwise?

OP said it already ran once. He didn't say it drove,lol.
Of course it will run. It's just a matter of synchronizing the sparks. But if the engine is counter rotating.lol, it will go very fast in reverse/very slow in forward gears,and probably tear up the tranny. But I 'd sure like to see that,lol.
But in order for it to start and run,as already sortof said; the cam,the distributor,the intermediate gear,and the starter,are a set; and I imagine the oil-pump will be different as well.
So the first thing to do, is see in which direction the crank is turning during cranking, and then see if the valve events are correct for running in that direction. If the D has a vacuum advance, and it was designed for reverse rotation then the Vcan will be in a different orientation from standard.That's an easy confirmation.