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Headlight vacuum and tach hole size

89yjred

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Does anybody know the hole size in the firewall for the headlight vacuum hose grommet and the tach wire grommet? I would like an actual measurement off of the holes in the firewall. I believe they are around 1-7/16" and 13/16" Also, there is a dimple in the firewall for the tach wire hole location, but not one for the vacuum hose. Can someone give location measurements for the headlight vacuum hose grommet location? I installed a new firewall on my build and these holes need to be cut out.
Thanks for the help.
 
Just checking to clarify for others here....are we to assume this is for a '68 Charger?
 
Just checking to clarify for others here....are we to assume this is for a '68 Charger?
Correct. Not to sound like an ahole, but that's why I put it in the 68-70 Charger forum. I figured everybody would realize it was for a Charger if it was in this forum. Although I know now days you have to ask because people just feel like doing what ever they want.
All 68-70 Chargers had the headlight vacuum grommet and the tach wire grommet in the same location just trying to get some info.
Would you happen to have any info or can you point me in the right direction?
 
Last edited:
Not sure if this helps but here is a pic of a 68 Charger firewall with the vacuum grommet location. It is a 1 3/8" hole.
Pretty obvious that a Chebby guy had it with the cobbled up wiring and black engine compartment.
No info on the tach wire.

100_6066.JPG
 
Not sure if this helps but here is a pic of a 68 Charger firewall with the vacuum grommet location. It is a 1 3/8" hole.
Pretty obvious that a Chebby guy had it with the cobbled up wiring and black engine compartment.
No info on the tach wire.

View attachment 1279347
That helps. Thanks for the info, appreciate it.
 
Not sure if this helps but here is a pic of a 68 Charger firewall with the vacuum grommet location. It is a 1 3/8" hole.
Pretty obvious that a Chebby guy had it with the cobbled up wiring and black engine compartment.
No info on the tach wire.

View attachment 1279347
Sixpactogo, Did you get that 1-3/8 hole measurement right from the firewall? I found a guy by me with an original 68 Charger and his headlight vacuum hole measured 1-7/16" and the tach wire hole measured 13/16". He had an AMD firewall that the hole measured close to 1-1/2". I ask you because I'm wondering if the firewall holes were stamped as inconsistent as everything else Chrysler did. Thanks again for the help.
 
Sixpactogo, Did you get that 1-3/8 hole measurement right from the firewall? I found a guy by me with an original 68 Charger and his headlight vacuum hole measured 1-7/16" and the tach wire hole measured 13/16". He had an AMD firewall that the hole measured close to 1-1/2". I ask you because I'm wondering if the firewall holes were stamped as inconsistent as everything else Chrysler did. Thanks again for the help.
I cheated. I measured the grommet from a spare vacuum harness I have thinking that would be the size of the hole. Sorry bout that!..............Anyway, I pulled the grommet out of my firewall and got the 1 7/16" measurement you mentioned. Here is a pic of where I came up with the 1 3/8". Looks like the hole is a 1/16" larger to give the grommet a little wiggle room.
100_0409.JPG
 
I cheated. I measured the grommet from a spare vacuum harness I have thinking that would be the size of the hole. Sorry bout that!..............Anyway, I pulled the grommet out of my firewall and got the 1 7/16" measurement you mentioned. Here is a pic of where I came up with the 1 3/8". Looks like the hole is a 1/16" larger to give the grommet a little wiggle room.View attachment 1280003
Cool. Thanks for the help.
 
There is a dimple for for the headlamp vacuum hose grommet!
Grommet.jpg
 
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