>>1602247>what parts would I need to fit a modern 10-11 speed RD?One of these adapter claw things. I think you may be able to just unscrew your RD from its plate and screw another one but make sure.
The caveat is that they're steel so if you get a bump there you'll damage the derailleur instead of bending it.
I would recommend a 7-9 speed setup anyhow since you'd save on having to get new chainrings or crankset and could just change the freewheel and add a longer spacer to ithe axle if necessary if you pick 7/8s.
