Difference between Windsor and Romeo Crank??

I know That the Windsor crank has an 8 bolt pattern and the Romeo has a 6 bolt pattern but is there any other difference. I have a Windsor block but my stroker kit came with a crank for a Romeo block. I know I’m going to have to got a new flywheel but is the crank pulley any different? On my old motor (Windsor) the crank pulley had a indent and the crank had a protruding groove so they would slip into each other and not slip but on the new crank there is a inward groove. So my question is are the crank pulleys any different with these two cranks. These cranks are interchangeable right??

Thanks,
John