Im swapping gauges in my buddies car and not sure what to do with the vehicle speed sensor. The autometer set is going in a 1988 IROCZ with a mec. speedometer.

So what am i supposed to do with the VSS on the stock gauge and the computer input?

 

The ECM still requires the VSS input. You may be able to find one of the old style geared speedo cable splitters used on many GM vehicles that had cruise control. These provided two cable outputs - one for the speedo head, and one for the cruise control unit. My '71 Olds had one, as did my '78 Cadillac.