I have been considering switching my Centurion to brifters eventually and trying to figure out the cheapest and easiest method. The frame has Shimano 600 7 speed with 126mm rear spacing. From what I can tell there are no 7 speed brifters that would work as a bolt on with my 600 group. Maybe the Shimano Tourney but that might be a downgrade in quality from my downtube shifters.
I am also planning on doing a frame off restoration and getting the frame repainted down the road so the other option would be finding a good deal on a more modern 8,9 or 10 speed group and cold setting the frame to fit bigger hubs. If I go that route does this look like a good way to cold set?:
The Plano Cyclist: Cold Setting A Bicycle Frame
I would usually take Sheldons advice but this method looks easier and more precise than the 2 x 4 method.