Where is the tach on a 68 dart?
Not the best picture but look in front of the shifter, you can see the factory tach, FYI, you could also have ordered a clock option, it looked just like the tach but had a different face, also mounted in this location. Your console top should have some holes for this, if not the lid was probably changed cause often people don't think this is correct and replace it with a diffefent console top plate. Does your car have the console yet? Maybe pull it and see it the original wiring harness is there, hopefully it is!
Not the best picture but look in front of the shifter, you can see the factory tach, FYI, you could also have ordered a clock option, it looked just like the tach but had a different face, also mounted in this location. Your console top should have some holes for this, if not the lid was probably changed cause often people don't think this is correct and replace it with a diffefent console top plate. Does your car have the console yet? Maybe pull it and see it the original wiring harness is there, hopefully it is!