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#2391055 - 10/22/17 12:28 AM Firewall grommet hole for tachometer
340clone Offline
mopar

Registered: 11/28/04
Posts: 470
Can anyone post a pic of the correct location for the firewall grommet hole for a tachometer on a '72-'74 B-body? (Or describe the exact location)

I know that '71 uses an existing connector on the firewall harness plug, but later years are supposed to have a dimple somewhere on the driver side firewall that marks the spot.

Thanks!


Edited by 340clone (10/22/17 12:29 AM)

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#2392129 - 10/23/17 10:37 PM Re: Firewall grommet hole for tachometer [Re: 340clone]
NachoRT74 Offline
master

Registered: 08/14/07
Posts: 5054
Loc: Caracas, Venezuela, SouthAmeri...
Actually as far I recall, 74s also uses the only cavity left empty on NSS harness plug. 72/73 uses the grommet. There are couple of threads with this info at FBBO board, just can't post the link right now.

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#2392177 - 10/24/17 12:37 AM Re: Firewall grommet hole for tachometer [Re: NachoRT74]
dart4forte Offline
I Live Here

Registered: 01/31/03
Posts: 14357
Loc: Mesa, Arizona
Here ya go


Attachments
71 B Body Firewall.jpg

71 b Body Tac Grommet.jpg



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#2393228 - 10/26/17 12:38 AM Re: Firewall grommet hole for tachometer [Re: 340clone]
340clone Offline
mopar

Registered: 11/28/04
Posts: 470
Thank you! What year cars are the firewall pics from?

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#2393232 - 10/26/17 01:06 AM Re: Firewall grommet hole for tachometer [Re: 340clone]
dart4forte Offline
I Live Here

Registered: 01/31/03
Posts: 14357
Loc: Mesa, Arizona
71 Road Runners

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#2393243 - 10/26/17 06:11 AM Re: Firewall grommet hole for tachometer [Re: dart4forte]
T2R9 Offline
top fuel

Registered: 08/12/07
Posts: 2488
Loc: Conway, SC
Here is a picture of my 71 Road Runner engine compartment. You can see the plug just to the right of the master cylinder next to the bottom of the clutch reinforcement plate.


Attachments
IMG_0534 (Medium).JPG


_________________________
1973 Charger SE 400 HP
1974 Charger Rallye 440
1978 Power Wagon 440 club cab, skylite
1995 Dakota Sport 5.2 5-speed
2016 Challenger R/T Shaker Plum Crazy

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#2393332 - 10/26/17 11:14 AM Re: Firewall grommet hole for tachometer [Re: 340clone]
340clone Offline
mopar

Registered: 11/28/04
Posts: 470
Thanks for all of the photos! I was able to reference a '73 Charger with a factory tach and the hole with plug was in between the M/C backing plate and the harness block. On my '74, the harness plug that goes through there contains all of the A/C wiring that goes out to the engine bay. Must have been a change after '73. Does any one happen to have access to a '74 that may have had a factory tach? Thanks!


Edited by 340clone (10/26/17 11:14 AM)

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#2393391 - 10/26/17 01:16 PM Re: Firewall grommet hole for tachometer [Re: dart4forte]
71birdJ68 Offline
master

Registered: 02/09/12
Posts: 3955
Loc: Morristown Tn.
Those aren't 71 B bodies.

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#2393538 - 10/26/17 07:51 PM Re: Firewall grommet hole for tachometer [Re: 71birdJ68]
dart4forte Offline
I Live Here

Registered: 01/31/03
Posts: 14357
Loc: Mesa, Arizona
Originally Posted By 71birdJ68
Those aren't 71 B bodies.



Yes sir, I stand corrected. Had to look again. I got the pics off a 71 B Body site.

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#2393546 - 10/26/17 08:12 PM Re: Firewall grommet hole for tachometer [Re: dart4forte]
71birdJ68 Offline
master

Registered: 02/09/12
Posts: 3955
Loc: Morristown Tn.
Just didn't want to confuse the OP.

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#2394188 - 10/28/17 10:53 AM Re: Firewall grommet hole for tachometer [Re: dart4forte]
NachoRT74 Offline
master

Registered: 08/14/07
Posts: 5054
Loc: Caracas, Venezuela, SouthAmeri...
Originally Posted By dart4forte
71 Road Runners


imposible... thats A or earlier B, never 71 and later B

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#2394189 - 10/28/17 10:55 AM Re: Firewall grommet hole for tachometer [Re: NachoRT74]
71birdJ68 Offline
master

Registered: 02/09/12
Posts: 3955
Loc: Morristown Tn.
We got it straightened out. Actually an E body would be the same I would think.

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#2394194 - 10/28/17 11:00 AM Re: Firewall grommet hole for tachometer [Re: 340clone]
NachoRT74 Offline
master

Registered: 08/14/07
Posts: 5054
Loc: Caracas, Venezuela, SouthAmeri...
Originally Posted By 340clone
Thanks for all of the photos! I was able to reference a '73 Charger with a factory tach and the hole with plug was in between the M/C backing plate and the harness block. On my '74, the harness plug that goes through there contains all of the A/C wiring that goes out to the engine bay. Must have been a change after '73. Does any one happen to have access to a '74 that may have had a factory tach? Thanks!


74 bulkhead disposition, cavity 4, NSS harness BH plug

As mentioned, just 72/73 are with grommet. 71s uses the engine harness plug cavity left, since AC uses the two left free on NSS harness plug ( these doesn't get the NSS ground into the cab like post 72 cars )



Attachments
IMG_3923.JPG



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#2399720 - 11/06/17 09:13 PM Re: Firewall grommet hole for tachometer [Re: 340clone]
340clone Offline
mopar

Registered: 11/28/04
Posts: 470
Well the mystery is solved! I had already bought the grommet type, thinking it was for a '74 so I will just drill a hole for it and make it look as factory as possible.

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