[Terry M. Hunt]

The attached photo is of my 66 GTO convertible with A/C firewall. The holes numbered 1 2 and 3 appear to have been drilled by some previous owner, not stamped by the factory. They are near the large hole where the accelerator cable passes through the firewall. I need to confirm whether these holes are supposed to be there and what their purpose is or if I should close them up.

[6d7gto]

My '67 non A/C firewall has them. Not sure what they are used for but eventually will find out if and when I ever get this project put back together! Hopefully someone will know and chime in for you.

[Cammer-6]

those holes indicated the screw is inserted from the inside.

[Terry M. Hunt]

The holes are deformed on the inside the way you would expect them to be if a sheet metal screw had been installed from the inside to attach something to the inside of the firewall, but what would that be?

[Jeff Hamlin]

As we all know the 3 holes closest to the Cable hole are for the cable cup/shield.
Anything beyond that could be anything on a 50+ YO car.

I would just weld them up.

[ZeGermanHam]

My '66 with A/C has those holes, but some of them were covered with with a dab of seam sealer at the factory. First photo below is during teardown on my car, and the second photos is after media blasting. You can see where they dabbed the seam sealer.

I don't know what they were originally intended for, but they are factory and were not used in my car before restoration and I didn't use them for anything when putting the car back together.

[Terry M. Hunt]

Zegermanham, thanks so much for these photos. My firewall also had these blobs of seam sealer until I scraped them off. I thought they had been put there by the guy who media blasted the car! I have made a template of the holes so I can recreate them if I decide to. At this point, I’m planning to close them up before I paint the firewall.

How weird that they created these 3 holes for no apparent purpose, or no purpose that anybody is aware of.

[Peter Serio]

Just my thoughts here. An old-style mechanical temperature gauge, the one with the hollow copper tube has a sensing "bulb" on the engine side. It's all connected as one piece to the back of the gauge. So that bulb needs a hole about as big as one of yours to get from the driver's side underneath the hood; and out to the intake crossover. Same with a real oil pressure gauge where hot oil is piped inside of the car directly into the back of the dash gauge.

A smaller hole than the temperature gauge needs, yes, but still an extra hole in the firewall.


Another one could very well be a mid-1960s era cable driven tachometer. (On a 1/4 mile car) They used to make a special distributor that had a take-off on the side where you thread on what looked just like a speedometer cable to drive the tach. One of those holes is big enough for that cable.

[Cammer-6]

Pete big hole is for accelerator cable
others have confirmed they have the same holes,filled with seam sealer,
just like the OP,so I would say Fisher body did that.
I ll be getting my 67 out of storage soon so will have a look.
Firewall on it has never been molested.

[Greg Reid]

Just curious so I took a look at mine. Seam sealer just like everyone else mentioned.

Sent from my moto g stylus (2021) using Tapatalk

[gto4ben]

Thanks for bringing this to our attention. Having engine fumes seep into the interior is anathema for me. On my 67 Lemans and 67 GTO Fremont assembled cars, #2 hole appears to be for the regulator mounting. I recall #1 and #3 were originally covered by black cemented cloth tape. You can see evidence of the tape on my LeMans. It's possible some plants used seam sealer.I don't see evidence that a screw was tightened in the #1 and #3 holes.

[428ho4spd]

Interesting to learn that one of these holes on my car was actually done at the factory. I just assumed it was drilled by the original owner that used it to run two wires through it for the old Sun tach that he installed. The other holes do have the original cloth tape over them. Apparently Fremont used tape instead of sealer.

[242177P]

Originally Posted by 428ho4spd

Apparently Fremont used tape instead of sealer.

X2. Here's an early 66 example of four tape locations
(voltage regulator has partially hidden one)

[Terry M. Hunt]

Here’s more info. I mounted an old voltage regulator which requires the use of hole number 2. I will be filling holes 1 and 3. The 3 holes needed for the voltage regulator are labeled VR in the photo.

[gto4ben]

I measured the witness marks from the cloth tape residue. It's about 1.25" long x 0.5" wide. I made some cutouts out of painter's tape to precisely apply the contact cement on the firewall and applied the cut cloth over the holes.

BTW, I think the hole in the center of the firewall may have been used for the underhood lamp. Can someone with an underhood lamp confirm this?

[Cammer-6]

looks like friction tape was used
or seam sealer depending on plant

[428ho4spd]

Originally Posted by gto4ben

I measured the witness marks from the cloth tape residue. It's about 1.25" long x 0.5" wide. I made some cutouts out of painter's tape to precisely apply the contact cement on the firewall and applied the cut cloth over the holes.

Nice job, Ben. I see they used longer pieces of tape on earlier builds prior to my car which has more square cut pieces, a cost cutting measure I'm sure.

[428ho4spd]

Originally Posted by gto4ben

BTW, I think the hole in the center of the firewall may have been used for the underhood lamp. Can someone with an underhood lamp confirm this?

Here's a photo of a Fremont built survivor with an underhood lamp.

[6d7gto]

Originally Posted by gto4ben

I measured the witness marks from the cloth tape residue. It's about 1.25" long x 0.5" wide. I made some cutouts out of painter's tape to precisely apply the contact cement on the firewall and applied the cut cloth over the holes.

BTW, I think the hole in the center of the firewall may have been used for the underhood lamp. Can someone with an underhood lamp confirm this?

I have the same configuration/same location in the center of the firewall as yours Ben. A hole on right and a dimple on the left below the lamp in 428's photo. Not sure if those bolt heads shown in his photo are holding the lamp in place or some other component? According to his photo, looks like the lamp is mounted above the seam but maybe the bracket is painted black hiding the bracket which is actually attached below the seam?

[428ho4spd]

Originally Posted by 6d7gto

I have the same configuration/same location in the center of the firewall as yours Ben. A hole on right and a dimple on the left below the lamp in 428's photo. Not sure if those bolt heads shown in his photo are holding the lamp in place or some other component? According to his photo, looks like the lamp is mounted above the seam but maybe the bracket is painted black hiding the bracket which is actually attached below the seam?

Hard to see in that photo, but the bracket is mounted below the seam. And the lamp is bent upward slightly on this car which makes it deceiving. I'll zoom in on the photo and attached it again here. I found a photo of another '67 survivor that I have in my files that I'll attach as well.