I have a '97 GT. i know it has the t-45, but not sure what kind of speed sensor it has. anyone know?

i just installed 4.10s and my speedo is way off, and i'm trying to figure out which way to fix it. If its electronic i'll just buy an xcal2.

Also, next year i'm probably gonna swap in a TKO 600. if i get it with an electronic speed sensor, what is required to adapt it to mine if its mechanical?

thanks

i had this posted in general tech but no one responded, so i figured i would try here.