I thought it would be a cool idea to swap the original Simplex Prestige derailleur on my 68 Raleigh Grand Prix for a more modern Suntour Cyclone, but NO CAN DO. The derailleur hanger won't accept the newer design and the dropouts aren't designed for it either. What would be a decent derailleur upgrade that will fit this bike? The Super Course for that year also had the Prestige. Is something a little later in the timeline like maybe Huret Jubilee a possibility? I'm not trying to keep everything period correct and have something like vintage campy ain't in the budget. I just want to tweak the ride and see what a difference a better derailleur might make. Any and all suggestions are appreciated. Thanks.