Delco radio wiring - Forums - Corvette C3 Registry Feb 25, 2013My radio is the stereo model but no wiring diagram is stamped on the unit. With the info you all provided I managed to get the speaker wired up only to discover the paper cone was torn apart. The wire leads were completely separated from the cone. Installing new Radio in 1970 Vette - Corvette Action Center wwwetteactioncenter››C3 Technical and PerformanceApr 08, 2008Installing new Radio in 1970 Vette Hey, I was at the Chevy Vette Fest here in Chicago. . I found that Clocks By Roger had completly rebuilt "origional" corvette radio's. He even had one for my 1970! However the price was over $500. The original radio was fed by a 3 wire connector. The 3 wires were yellow,black, and grey.