tach wire location?

could anyone show me a picture or describe to me where the grey tach wire is supposed to come through the fire wall on a 69 cuda.The car Im working on is a 340 clone and was not equipped with a factory tach,but is now being converted to a rally dash setup.From what I can see in the factory schematic the wire should feed through a rubber grommet .

thanx,justin
[email protected]