I have a '73 (I think?--block lettering, capella lugs) supercourse frame. It takes a 68mm English threaded BB (pretty standard--not the proprietary version). The length of the spindle will depend on your crank and the chainline you're after, but the spindle on mine is 113mm for a single ring up front and a fixed cog in the rear. This gives me roughly a 42mm chainline--not sure if this is what you're after with the Nexus hub in back, though.

I don't think there's any reason to spend that much money on a BB. This might be blasphemy but I've used the nashbar square taper BB with success (https://www.nashbar.com/profile.cfm?c...tom%20Brackets)
They'll probably have a sale soon (as long as the sun comes up in the morning and goes down at night).

Unless you're looking for a BB that will outlast the life of the bike, this should work.

I have a Raleigh Carlton 78 Supercourse. My frame looks pretty much like yours except for the chrome on the fork. Mine is copper colored rather than green. I used a Shimano 122mm UN53. THe 122mm length gave me the correct chain line. NOS Shimano UN** BBs show up frequently on eBay for ~$20. I think Sheldon Brown's Web site has a discussion of using the Shimano BBs on vintage Raleighs.

The frame arrived today and it looks like a 9.8 out of 10. A very small nick on the front fork, a couple of pin prick sized nicks on the top tube, and a slightly tired 531 decal spoil an otherwise mint frame. Now the interesting thing is, the lugs are not Capella. They are the later Supercourse II style lugs. I guess this frame was built at the end of the run of the standard Supercourse just before the arrival of the Mark II, making this frame to be a '74. It curiously has a Shimano shifter bracket and the brakes on it are Mafac Racers. I suspect this frame was in fact built up at one point using non stock parts.

I'll take pictures soon.

I suspect you're correct about the parts. Those lugs are Prugnats btw.

I put a Shimano sealed unit in my '74 Supercourse. The shell is 68mm. Any standard BB will fit. If you want to spend big bucks, sure, the Phil is a thing of beauty, but you don't have to. The spindle length will depend upon what kind of crank you're planning on using. Sounds like you're going with a single chainring. I went with a triple, so you might want a shorter spindle.

As promised the pictures of this frame can be found here:

https://www.flickr.com/photos/5860556...57604991958189

Update:

I just purchased an old TA crankset with chainrings of 54/42/28. I am inclined to use period correct components on this build and I would like to hear from other experts which front derailleur would be most suitable for this crank. I'm running a 6-speed freewheel with a first gen. Cyclone rear derailleur. Thanks in advance!

If you have the matching first gen. Cyclone FD, I'd try it and see if the cage is long enough to handle that spread. Here's a thread that'll give some guidance, too: https://www.bikeforums.net/classic-vintage/259246-suntour-cyclone-mk-ii-fd-capacity.html

Neal