Questions installing a tach

[idriveafordranger94]

Hey everyone. I drive a 94 Ranger 4.0L automatic. It came factory with the speedometer only gauge cluster. I want to install one from another 4.0L Ranger that has a tach. How do I do this? Will there be a wire that carries the rpm readings already there? What about odometer readings? Will it need calibrated? Thanks

 

[keith0486]

my question is why do you need a tech in and automatic truck?