Engine to firewall ground wire

[69GT]

On a 69 Dart, where does the engine to firewall ground wire attach? Big block if it matters. I was thinking from the rear of the block on the passenger side to one of the heater blower motor nuts.

 

[Murray]

Right rear intake bolt to firewall hole just for the ground wire, just to the left of heater motor bolts.

 

[Dana67Dart]

2x heat only firewall
1x AC firewall

AC FIREWALL
Red is the block ground

Yellow is the fan motor ground