[Terry M. Hunt]

Here are some pics of the firewall of my ‘66 GTO convertible with a/c. Notice the two holes above the heater core opening and how crudely they were cut. Like with a torch. Notice that the hole to the right has a finishing flange with tabs that bend over on the interior side of the firewall. That just seems odd to me that the factory would cut these openings so crudely. This is not a case of somebody adding a/c after the car was built as the PHS confirms it was built with a/c and there are no other indications of DIY being done on the car. If this finishing flange on the right is a factory piece, should there also be one on the hole to the left?

[Jeff Hamlin]

Since the AC models have nice rolled edge punch-outs from the factory,
It's possibly a case of one getting by and a quick on the line modification was needed??

Just a guess.

[ZeGermanHam]

That is rather unusual. Are there any other signs indicating that portion of the firewall may have been replaced/worked on by a previous owner?

Here is what the firewall looks like on my '66 post coupe.

[b-man]

I’d have to say that on the assembly line they discovered the mistake by the body builder (Fisher) who built the body with a non-A/C firewall for a car ordered with A/C and fixed it using a cutting torch and a grinder.

They corrected the mistake and kept the assembly line running. The car might’ve been yanked off the line for a time to effect the repair, who knows.

[Terry M. Hunt]

Thanks for the pics of your cars. Definitely show a neater/cleaner method of creating these holes. Looks like they were punched with a die that rolled the edges to the inside of the firewall. There is no evidence of the firewall being messed with any place else. The idea of this being a goof up at the assembly plant that was caught and “fixed” somewhere in the plant is intriguing. Just doesn’t seem to be any way to confirm this. The crude openings won’ t change how the car looks or functions once it’s put back together, but I would really like to know “what gives” with these openings.

[Terry M. Hunt]

If this was quick fix done at the plant, it seems really odd that they would take the time to fabricate the nice, neat sheet metal bezel to cover the jagged edges on the right side hole.

[b-man]

That neat sheet metal bezel was used on all the factory A/C cars if I’m not mistaken, it wasn’t custom fabricated to cover up the mistake on your firewall. I’ll try to find mine and get a picture.

[Terry M. Hunt]

Bman, was the finishing bezel only used on the right hand hole or was there one used on both holes?

[b-man]

Just the smaller hole on the right as seen in your pictures.

Perhaps it’s there to provide a better wider sealing surface.

[66sprint6]

That is wild. How about the huge plenum opening to the left? Is that altered?

[ZeGermanHam]

Originally Posted by b-man

That neat sheet metal bezel was used on all the factory A/C cars if I’m not mistaken, it wasn’t custom fabricated to cover up the mistake on your firewall. I’ll try to find mine and get a picture.

This. That metal bezel is standard equipment on all A/C cars. You can see that the hole the bezel is covering is jagged like the other, though, whereas on my car both openings have rounded edges.

[fyrffytr1]

Here's a picture from the inside of my 67 A/C car showing the bezel.

[Keith Seymore]

I'd go with factory assembly line fix as well.

I personally had one occasion where we had a pickup cab built incorrectly - no floor cutout for the manual trans shifter.

The mistake was discovered at body drop. In that case the repairman cut the floor opening with a hammer and chisel, while the fully trimmed cab was teetering on top of the transmission, and while the line kept moving.

I can only imagine what that repair looked like.

K

[Andre]

Does your factory build sheet indicate AC? I seem to recollect that you could get dealer add on AC for 1964 A body cars, but I don't remember if that was possible for 1966. Or maybe a previous owner added ac from a donor car, and had to simulate the holes in the firewall.

[Terry M. Hunt]

Andre, the PHS shows a/c and there is no other evidence of of a dealer install or previous owner a/c install. Everything else looks just like you would expect a factory install to look like. Keith, that is a wild story about the shifter hole. I guess anything any of us can imagine has happened on an assembly line at one time or another. I’ve been restoring these cars since 1977, but stuff like this still comes up that makes me realize none of us will ever know it all. It also makes me realize how lucky we are to have these forums to pool our knowledge.