I believe the tach grommet was feed through the hole punch above the bulkhead connector when the car was equipped with cruise control. I believe the grommet for the cruise utilized the "normal" tach positon.
As you can see on this '69 Charger R/T equipped with cruise, you can vaguely make out the single-lead tach wire harness out of the top position.
TroyHouston Mopar Connection Club'69 Charger Daytona 440 - auto - 4.10 Dana (now with 426 hemi)
'69 Charger 500 440 - 4speed - 3.54 Dana
'70 Road Runner 383 - 4speed - a/c (now with 440)
