Guys, I have a est. 3" in diameter hole in my firewall with a cable running through it. I had previously assumed that this was the cut out for speedometer cable but this hole was est. 1.5" in diameter;
I suspect that this hole in firewall has not been covered for the past 50 years as the floor pan /toe plate below it were seriously rusted from water running from the engine compartment into the interior.
I assume that there was some type of grommet for this hole but I have been unsuccessful in finding a plug or grommet larger that 1.5" in diameter. Can you help me solve this mystery? Thanks.