67-76 cars: Do they all use the same firewall?

The Heater hoses are in the same place but that is it.....

The blower motors are a different diameter. I'm currently welding closed the a/c holes and converting to non a/c on my 72 demon.

I used card board to measure and make a steel piece to weld in. Almost finished with the project in a few days.

You can see the location of the non a/c blower motor in relation to the a/ c version..

Other than the heater hoses being in the same spot, nothing is the same, even the insulation and insulation retainer holes are different, I have to weld some shut and drill out other locations

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