So I am a bit of a noob. Im will go ahead a apologize for this.

I have a 1980s Schwinn, not 100% sure on exact age. The original wheels are beyond repair. They got me around for a few months, So now I figured I would convert to 700c. I have searched around and Some people say when changing to a modern rear cassette older derailers and such wont work. Is this true. If I run a 8 speed cassette will it work with my original components.

Thanks for the help.