I'm looking for a Campy headset for my 75 Raleigh Professional rebuild. What's the difference between Campy Super Record and Nuovo Record components? On ebay, NR headsets seem to be a lot more pricey.

TSapp

Big difference in the headsets. Record (sometimes called Nuovo Record) headsets are durable, chrome-plated steel components.

Super Record headsets were arguably the very weakest link in the Super Record line, and are made primarily of aluminum, with steel bearing surfaces. Very prone to developing 'index steering.'

Generally, in NOS condition, Super Record is almost 2x the cost of Record (because everybody that has a Super Record headset needs, or will soon need, a new one)!

You don't want to buy a used Super Record headset (in my opinion). Very likely to be junk.

I think your sample is too small to make that statement, or there are other details of which there are plenty that change the dynamic of what draws a big price. Some folk get all excited over perimeter stampings.

Super Record has alloy parts with pressed in steel races for the primary visible parts.
It can get mucked up w/o proper tools.
Many used Super Record head sets are just that, cosmetically challenged.

For your frame unless you have to have Campagnolo get a Tange headset that appears like a Campagnolo, just avoid the 27.0 mm crown race, (JIS), you need 26.4.

Which should not be the case, but is. One could argue that without the decorative processing and discrete parts needed to make a Super Record, better steel could be used on the ground and heat treated race parts, and the Super Record COULD be superior.

The problem we had with Super Record headsets at Trek is that the crown race would easily split when installed if not done just right. The Super Record crown race is much thinner than the Record crown race in order to give the same stack height despite the necessarily thicker aluminum cups:



This also meant that the Super Record lower race was not as well sealed against contamination as the Record lower race.

What do you guys think the primary cause of the brinneling was? A less stable lower cup race or a lower crown race or a combination of both.

The only reason to buy Super Record is if the rest of your bike is Super Record and your looking to round out the group.

You forgot material or process choice. I don't know the answer unfortunately.
The Chris King headsets, even the very early ones did not have this problem. But there were less of them. Chris King might have an idea, I am sure he looked at what was existing when he got going, but intellectual property is just that.

I recently had the SR indexing problem on my Mclean. I had a spare used NR headset to replace it, but chose to keep the upper SR parts and used the NR parts on the bottom. Worked out well enough and keeps the (mostly) SR group/look on the bike intact.