Is it an electrical vss? I just bought an 84 Corvette last year, and the vss in it is messed up and was even the wrong one. Rather than remove it from the transmission, nd probably find the gears in the tailhousing missing or the wrong ones too like the vss was, I bought a gps speed sender. It can output 4000 or 8000 pulses per mile. The 84 Corvette uses 4000, and sends that to ecm to divide by two to control the tcc. Later years Corveetes used 8000 pulses per mile that went to the ecm first then the digital dash.
If yours is electrical, you might want to try the gps sender because if you ever change the transmission, or change the tires or rear end, you wont have to do anything. The intellitronix one thy say updates a little less often than the veethree one. There are others too. I bought the intellitronix one.