Heater Fan Motor Mod for Added Engine Bay Clearance

I started putting the heater box back together , The Cuda is still in Body Shop Hell.....
It looks like the factory blower motor sticks out about 2 3/8 " from the firewall . The shorter motor sticks out 1 5/16"
About an inch shorter without any heater box mods.
Is this enough clearance , or do I need to cut the box to move the motor in some more ?
How far away is the head from the firewall on the BB A bodies?
Cant wait till warm weather here in Ohio .
Here's some progress pics
I also see some differences between the 67 and the 68 Heater boxes , both are off non AC fastback Cudas' . The cable attachment points are different as seen in the pics
Donnie

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