Car: 1972 GS Stage 1 with Auto Trans and A/C. I have some holes in the firewall that I need some help understanding what they are for and if they need grommets. I have added some pictures to better describe my questions. 1) There is a small hole to the right of the voltage Regulator. What is this hole for? 2) There is a 1.75" hole to the right of the Blower Motor Relay. I believe this hole is for the wiring for the A/C controls in the dash, coming from the engine bay. I believe this hole uses the 1.75", single hole grommet. Can anyone confirm? 3) What is the square hole to the right of the throttle cable for? 4) Do I need the 3 hole (2.25" diameter) grommet that is used for A/C vacuum lines? If so, where does this grommet go? (I don't have any 2.25" holes in the firewall). Thanks in advance for your replies and knowledge!
Here are a few pics of mine that I’m restoring. Car is a 70. The hole to the right of the regulator is for the rubber push grommet from that is for the firewall pad. The large hole uses the 3 hole AC grommet for the AC extra harness and vacuum lines. The brown wire is the tach wire. It’s not suppose to go there since my car didn’t come with a tach. Just in case I want to add a tach, the wire is there. I have to remember what I bought for The square hole by the throttle cable. I believe I got it from Ames Pontiac. Possible called kicked down cable grommet. It was a plastic piece that just pressed into the hole. This should be what I bought.
Utah455, Thanks for the response and pics. Strange thing is, the hole I have in my firewall is 1.75". so that would drive me toward the single hole 1.75" grommet. The 3 hole grommet (like your picture) is 2.25". This is the ad description: 3 HOLE FIREWALL GROMMET WITH METAL CORE 2" (MOUNTS IN THE MIDDLE OF FIREWALL ON CARS WITH A/C & ALLOWS THE VACUUM LINES TO PASS THROUGH IT. HAS A RUBBER COATED STEEL CORE. IT IS 2 1/4" IN DIAMETER). So, I am concerned that the larger 3 hole grommet won't fit in the 1.75" hole. My quandary continues. The rubber push grommet for the firewall pad makes sense - thanks for that pic.
