I'm overly critical about aesthetics. There's the nice curve of the cup, then the straight line of the tapered cone, then a spacer that seems too small, then the tapered top nut. 2 flats on the cone and 4 flats on the top nut.

It's like they were trying to get at this style, with 4 different designers working separately:

Oh. Well, in my pic the spacer is my own and not included with the headset. There is a thin lock, keyed washer that is included and is not the same diameter of the rest of the headset. I see you what you mean, it just doesn't bother me to the same degree, I guess.

Me? This is the best pic of the HP-6500 I have handy.

Is this unit a 26.4mm crown race (ISO), British thread?

I think I just read on Vintage Trek of steel racing frames (700 and above) coming with Campy Super Record, but I don't recall what year the catalog was for.

My 84 Trek 660 came with Stronglight B10 headset, it was a really nice and real light weight headset. I put about 130,000 miles on that headset and it's still good to go, but I replaced it with a Superbe headset because I like silver better then black, but I still have the Stronglight. I'm thinking about putting the Stronglight on my Fuji Club when I change out the original steel fork for a aluminum one that I just finished polishing to a near chrome like appearance.

In reality headsets rarely fail if their properly maintained, the need for a $75 to $130 plus headset seems crazy too me. I have cheap arse Walmart bikes that are 20 years old now, left out in weather, crashed too many times to know, and the headsets are still fine; my parents have old three speed Schwinns they bought in the 50's that still have their original headsets; I've never had a headset fail. I think the Tange Levine LV1500 is more then good enough for the high mileage rider, in other words it will probably last a lifetime of normal riding.

To me, the attraction of sealed bearing, cartridge bearing headsets is not that they will last longer, but that they are infinitely faster and easier to setup accurately. From the first moment I installed one I thought "damn, all headsets should be this good". I can honestly say that I can feel the difference in a cartridge bearing headset and a properly setup loose or retainer ball headset. It's just a personal thing and, to me, those $50 headsets were worth every bit of the extra $30 as opposed to an older style unit.

The models that were spec'ed with Campy (970, 770) got Campy headsets; the models that were spec'ed with Superbe (760 -- same frame as 770, just different components) got Stronglight A9. IMHO, the A9 is a better headset than the Campy: both lighter and more durable.

Justin brought down the house. boom.

Another vote for the VO headsets. Shimano Ultegra headsets are also very nice but hard to find since they don't produce them any more. You can still buy them on eBay but will probably cost just as much or more than the Velo-Orange.

My wife has (really, had, just replaced) this same headset on her Trek 610. It always flexed a lot and fit the frame poorly. I could never get it where it didn't have some play. If I removed the fork, the bottom plastic cup would just fall out of the bike. It wasn't inspiring. I always felt like it was a real shame that the bike came with the plastic B10 instead of the metal one. Otherwise, the bearings and races were fine and I liked the uniqueness of it.

Are you describing the Tange Levine headset?

^ I would guess a Stronglight B10?

The plastic cupped Stronglight headsets that were used on Treks in the 80's weren't really bad as some might suspect them to be as I never ever heard of problems with them cracking or breaking up under use (except maybe in case of a bad crash). Remember, the plastic cups do not really take any wearing loads as there are separate steel bearing races in the headset that takes that. In the end, if you do want to use a non plastic cupped Stronglight headset, you can't go wrong with the aluminum cupped A9 and the Delta as they are pretty much the best designed headsets in the 80's.
The Miche Primato needle bearing headset is also a good one and a good value to boot at only around 40 bucks brand new. Pretty much a direct dopy of Stronglight designs. I have one on one of my bikes and it has never given me any problems yet. Its aesthetics look a bitmore modern than the Stronglights and will look nice on later 80's bikes with aero themes on it.

Chombi

Weird, I never had that problem with mine, there was no play or flex in that fork even after 130K miles, I kept the headset because it has no issues, even the bearings are the original bearings!

It sounds like it was never adjusted or installed correctly either the bearing retainer was installed upside down which does happen more then a person would think, or the bearing races were installed crooked; either that of the fork was slightly bent, or the head tube and fork crown were not faced correctly or perhaps damaged in a crash. Unfortunately I never knew anyone who had that headset to know if there was an issue, however no issues were ever reported on the internet when I looked.

I suppose any of those things are possible. I know the issue went away when I installed a new headset. I have read posts where people say these B10s flex more, but I just couldn't get it where it wouldn't wobble a bit (you know, when you apply the front brake and push). I did mess with it for a bit, but when the bottom cup just keeps falling out of the bike (when fork removed), well, I just figured it was time to replace. It was too bad otherwise, the bearings and races were fine. I can't help but think that I wouldn't have had that problem with a metal headset; this is the only headset cup I've seen that just falls out of the bike. Perhaps it was a manufacturing issue and not endemic to the plastic. I wouldn't buy a NOS or used one in the future; that said, if I had one on a bike already and it didn't have the issue, I don't know if I'd go out of my way to replace it either.

Well at least you got it taken care of. I think more to the point thought that the original posters Trek bike came with a Tange headset, those are really nice underrated low costing headsets. If he opts for the Tange he would be putting the bike back into factory stock appearance if that's important.