Car is an '88 Trans Am GTA, (hardtop/5.7/auto). A few weeks ago, I noticed in the engine compartment that on the drivers side of the firewall, there was an open hole through which I could see the interior firewall insulation. There was no scuff ring or dirt marks around the hole indicating that there was ever a plug to seal up that hole. I looked online to try to find what the hole was for, mainly so I could identify the size hole and get the factory grommet or plug for it. However, I was unable to figure out what the hole was meant for. It is definitely a factory cut hole. It is perfectly round, no burrs, and the inside edges have perfect paint.
I ended up getting a measurement from it of right about 1.25" in diameter so I just ordered a rubber body/firewall plug. But what is/was it for?
I found this picture online which shows some larger cable or rigid hose going through it. I'm not sure if this is factory or an aftermarket thing though. Cruise control hole is lower, clutch master would be lower, hood cable hole is over to the right more. I just can't figure out if I'm missing something and if so, what am I missing.
Edit: oh wait, is that the hole for the old mechanical speedo cable for 82-84/85? birds and 82-89 camaros?