1971 tachometer quit.

[per5069]

I HAVE A 1971 CORVETTE 350 ENGINE WITH 10000 miles on it. I'm scratching my head. What am i missing? My tachometer stopped working. Threads say bad tach drive gear. I pulled the cable off the drive and the end of it looks round, definately not square. Pulled the gear and it looks good. Have a new cable, plugged it in the distributor and it turns clockwise. The original cable turns the tachometer counterclockwise to show RPM's. I cut the crimp on the old cable to lengthen the cable so the square will work in the drive gear. Still no tachometer RPM's are showing. Anyone ever have this issue? Any help is appreciated. Thanks