I think they are. They one i bought from napa for my 340 dart is adjustable, the one that came on my replacement distributor for my 383 is also adjustable... I think the adjustable ones are hex shaped instead of round ? I may be wrong on that though
Getting over my head here, but I assume you are talking about the diaphragm on the distributor. How do you adjust them? I just replaced my distributor since it was 50 years old and don't see how to adjust the new one.
