I do have one more question which should be pretty basic. If I can't get my Shimano 600 friction downtube shifters to work adequately again, will a newer set of downtube shifters work with my old frame and 600 derailleur? That is, can you tell me if the downtube shifter bosses have changed dimensions in the past 20 years?

I found out last night that a newer set of shimano 600 brakes would not fit my older frame because the hardware would necessitate drilling the brake mounting holes out to make them bigger. Fortunately, I was able to use the springs and bushing from the newer brakes to rehabilitate the older stoppers.

DanO