I'm slowly swapping from a C4 to T5. I got the pedals hanging but I don't see where the clutch rod passes through the firewall. I read that they should be a knockout already stamped in the firewall. A picture sure would help.
I converted my car from an auto to a standard not too long after I got the car back in 89 so I'm a bit fuzzy on the details but I do remember some sort of perforation on the inside of the firewall but there were more layers than one to go through. Today I would have just put the correct hole saw in my drill and be through in a minute but back then, I remember hacking through with the few choices of tools that I owned at the time. Here is a photo but wait until you get more verification of it's location before following my lead just to be sure.
Taking a second look at your photo, it appears that you have a single dimple in the same spot where I made my clutch rod hole.
Yep I agree the dimple is there, here is a pic from the engine compartment of mine. I'm not using mine...went to automatic...want mine?
After looking through all my pics when I soundproof my interior I couldn't see a dimple. I think I found it when looking under the hood. For some reason or another the paint is peeling in a perfect circle what needs to be drilled out. Now getting a drill motor in there to drill a pilot hole is gonna be fun...barely got the camera in there. I can cut the hole from the other side easy once I drill through 3 layers of Peel and Seal
This may help. I also see what looks like a dimple to the lower left of your master cylinder rod hole. Here's a clear shot from the engine bay that shows it pretty well.
When I had my car in Oregon last week I was thinking of welding up mine, except the rod still goes through the firewall.........which is attached to the pedal and that heavy spring keeps it on the floor for my left foot to rest on.......................although I have to admit at least twice I tried to shift the automatic with the left pedal
make sure the hole is not too large so the rubber boot will fit snugly. if it's too large a diameter, it will just ride through the firewall uselessly. or just glue it in like i did!
IF I remember correctly .. there was a circle cut in one layer of the double layered sheet metal on the firewall. Forget if it was inside or outside. But .. Like Tody said .. don't cut out the entire circle like I did ... The OEM clutch rod boot slid right through. I ended up have to use a GTO boot to fit the hole I made. Get the boot first to determine how big to make the hole.