Searched speedo.Mines electric. Help

I searched for speedometer calibrating,ect, and all i come up with is replacing the driven gear,for correcting for changes in axle gearing. My 95 vert has an electric speedometer hookup at the trans. I switched to a tko 500 and plugged in the speedo and it was WAY off. As I came down the ramp on the interstate the speedo rolled right on around the dial and kept going all the way to 90mph the second time around Which cars came with a cable drive ,and which came with electric??? How do i recalibrate for the TKO?

EDIt- I found it http://forums.stangnet.com/showthread.php?t=585540&highlight=speedometer+cable