Strange hole in firewall.

[longhorn70gmc]

This is a great question to ask. I go the same answers as to the pictures show and I discovered it on a 1968 LWB Chevrolet. I also found the rubber grommet that goes there as well still on the truck. Picture in your mind a Oval shaped like an egg and then it has a rubber sheath coming off of it about 2 to 3 inches long. This is what the linkage was routed through. I view the hole as godsend, so I don't have to make anymore in my fire wall. I am currently using it for my Vacuum gage line and when I finish the TAC it will also go through this whole. The grommet is hard to find because I admit I have been trying everywhere including the internet, but removed the old grommet from that 1968 and have refurbished it with High Temp Black RTV to make it fresh again until I find a nice new one. I am going to go find some kind of packing to fill it when I am done to keep the rodents out of the cab. I just redid my seats. Good Thread and am glad you asked.
R/
Billy