My 69 Camaro has a hole through the firewall immediately behind the distributor, near the ground strap screw from the RH valve cover. The car has the special 'rivnuts' in the transmission tunnel for mounting a console, and the in-dash tachometer, so I'm thinking it may have been a factory gauge console car. The issue is that the 69 AIM, UPC 0, shows that hole for the oil line as being 0.5" in diameter. The hole in my car is slightly smaller, around 3/8". Hard to measure, so I used the shanks of different sized drill bits until one passed through. The AIM doesn't show any other factory piercings nearby. Could this still be a factory oil line hole, despite the smaller size? Anyone else found this hole to be undersize? I assume the hole size would have been specified to suit the oil line and grommet size.....
FWIW, car was assembled at Van Nuys, 04A, in case this is relevant.