I put a 13-26t Suntour U-6 freewheel on my 1970's Masi GC, using the original NR derailer. I did have to add 1mm to the right side axle spacing, no big deal, but are you talking about "unmentionable" current CHAINS? Not sure what you meant.
I went ahead and used a current chain. It made the whole switch possible with such narrow (equivalent to current 7-speed) cog spacing. The period-correct narrow chains can't compare in terms of shifting or chain life. Suntour's DID-made narrow chains wore out quickly and are relatively noisy. Their greater width vs. current 7-8sp chains made shifting sloppy, too.
I ended up with the smallest cog so close to the dropout that the high-limit adjustment became critical lest the chain contact (noisily) the lower edge of the dropout, but chainline and wheel dish is best this way on my bike.
Going further off-topic, the new "8-speed" chain that I chose (a sharp-looking, inexpensive Sunrace CN-91 that requires no special links or pins) produces shifting as good as with any Suntour U6 freewheel I've ever used. I have also used 7-sp indexed shifters with such narrow-spaced freewheels as these in the past, (Suntour U6, Maillard Compact-6, Maillard Helicomatic) but I have renounced such feeble "enhancements" on my current stable.
The modern chains really can make the parts-matching process much more forgiving, however, and last week I grudgingly fitted a local Senior's ex-TDF, C-Record Lemond with a 7-speed Falcon 13-28t freewheel and those Synchro shifters have never worked better! I experimented with a 7-8sp HG91 chain and a SRAM 9-sp chain while optimizing the chain length, and both worked really well.
David Snyder
riding out into the heat in
Auburn, CA
>I was talking with Mike Kone at the Cirque (a veritable fount of wisdom,
> I have to say, hats off to ya, Mike), and he mentioned that it is
> possible to put a Maeda ultra-6 freewheel on a hub spaced for a 120mm
> rear-triangle, and use the current
> Campagnolo-parts-that-can't-be-mentioned with it.
>
> Is this the case, or am I mis-remembering? I'll talk with Mike
> off-list, but I also thought this an interesting issue--getting some
> modern parts-that-may-not-be-mentioned on a vintage frame without
> re-spacing..and I thought others here might be interested in it, or have
> other comments.
>
> Please e-mail me privately, as well as to the list...since I don't see
> every post.. and note that I'm not trying to make this about new
> components. I'm trying to understand how to put new wine in an old
> bottle...
>
> Thanks.
>
> Charles Andrews
> Los Angeles