Mystery hole in firewall?

[TrinitySteve]

When I bought my 69 panel, most of the firewall and interior had been stripped for painting. Now that I am beginning reassembly, I have an extra hole above the heater box and I can find no reference as to its purpose. This is a "no a/c" truck.
Any ideas?

[LockDoc]

Originally Posted by TrinitySteve

When I bought my 69 panel, most of the firewall and interior had been stripped for painting. Now that I am beginning reassembly, I have an extra hole above the heater box and I can find no reference as to its purpose. This is a "no a/c" truck.
Any ideas?

I'm bettin' at some point in it's life it had an aftermarket A/C in it. Here is a picture of my '67 Panels firewall with the A/C line holes in it. Mine looks bigger but it is bigger than it needs to be..... My unit is a Mark IV under dash.

LockDoc

[TrinitySteve]

Thanks, LockDoc. The hole looks factory or someone did a really good job. The a/c makes sense, in fact I had thought of routing my lines there. I am wanting to do an underdash unit. Any info on the Mark IV?

[Bigdav160]

Could have been a dealer installed unit.

[LockDoc]

Originally Posted by TrinitySteve

Thanks, LockDoc. The hole looks factory or someone did a really good job. The a/c makes sense, in fact I had thought of routing my lines there. I am wanting to do an underdash unit. Any info on the Mark IV?

No, I really don't have any info. I don't know if they are even made any more. Once in a while you see them on E-bay or Craigslist. Most of the guys are using the Vintage Air or other newer style ones.

LockDoc