Firewall plug - AC cable hole

[benguin]

While waiting for my master cylinder resleeve, I thought it was a great time to clean up and repaint my booster.  During the process, upside down and under the dash (you know the position), I noticed a small firewall hole with no plug.  The handy reference doc on this site for firewalls says this is for the A/C cable.   My care does not have (nor has ever had) air conditioning.

So- what plug is supposed to go in there?  It's too small for the typical body plugs. I have looked at DMC's e-body firewall kit, but nothing listed for the A/C cable plug.  Does it exist?  Or just left unplugged?  With the booster in place, it clearly isn't easily visible.

Appreciate any insights!
  Ben

[anlauto]

Other holes roughly that size and location were used on four speed cars, for the clutch pedal safety switch. On 70-71 Cuda for road lamp wiring, or perhaps someone just made a hole for something aftermarket over the past 50+ years

[benguin]

Hi Alan, my road lamp wiring is going through the expected hole for that, and looks like it's in a factory spot, but should have a plug.  Not sure why it's drilled. I've had this car for a very very long time, and it's in the spot as shown on the firewall.  I was tempted to put an insulation push pin through there, but the hole is smaller than that. 

I was hoping someone else with a '70 non-ac car would take a peek to the left of the steering column between the speedo plug and the plug for the manual washer  is and tell me what plug might be there, or "no hole".  Mine is a Nov '69 build, if that makes a difference.

Here's the reference section for that hole: https://forum.e-bodies.org/reference-material/18/e-body-hole-locations-firewall-door-interior-ect/303/

Thanks!
  Ben

[benguin]

Closing out this thread- confirmed that for non-a/c cars that hole is used to secure the insulation with one of the Christmas tree push pins. 

Mystery resolved!