Topic: 4-speed '66--Plugging Original C4 Speedometer Hole?

[drummingrocks]

I was working on my 4-speed '66 fastback today, and I realized that ever since restoring the car, I've had the speedometer cable passing through the firewall in the wrong place.  I always thought the cable was a little short, guess now I know why: I had it passing through the hole for C4 and 3-speed cars.

I've got it rerouted to the correct hole transmission tunnel near the gas pedal, but now I'm wondering what originally plugged off the other speedometer cable hole in the firewall for C4 and 3-speed cars?  I wish I had taken better pictures of this area before I restored the car, but that's water under the bridge now.

This is a Dearborn '66, built December 8th, 1965.

[J_Speegle]

Any sheet metal work/replacement during the restoration?   Or did a PO have an auto in the car?

[drummingrocks]

Yes, the floor was replaced with a one-piece floor pan, and part of the RH toe board was replaced as well.  The firewall is still original--it hasn't had any work or repair done below the steering column on the driver's side.  The correct 4-speed speedometer cable hole is still in the transmission tunnel, to the right of the gas pedal.  As far as I know, the car has always been a 4-speed car.  According to the original data plate, it was a 4-speed car when new. 

Being a 4-speed car from the factory, would it have even received the hole in the firewall that a C4/3-speed car uses to route the speedometer cable?  I assumed that all Mustangs regardless of options received that hole, and that on 4-speed cars, an additional hole was punched to the right of the gas pedal to route the 4-speed speedometer cable.  Of course, I'm probably way off base--you know what they say about assuming!   

[J_Speegle]

Being a 4-speed car from the factory, would it have even received the hole in the firewall that a C4/3-speed car uses to route the speedometer cable?  I assumed that all Mustangs regardless of options received that hole, and that on 4-speed cars, an additional hole was punched to the right of the gas pedal to route the 4-speed speedometer cable.  Of course, I'm probably way off base--you know what they say about assuming!   

Not certain all cars got the automatic hole or if no used what would plug it (to keep water, fumes..... out

Need to see if I have some pictures that can provide anything to the discussion - maybe someone with an original manual 66 can check theirs and report

[CharlesTurner]

The hole would be plugged with a rubber grommet...

[J_Speegle]

Thanks Charles was just drawing a blank on that one

[CharlesTurner]

Thanks Charles was just drawing a blank on that one

Easy to think the hole wouldn't be there on a 4sp, but seeing it on all original floors no matter what trans.

[drummingrocks]

The hole would be plugged with a rubber grommet...

Thanks for the picture.  I feel better knowing that that 2nd hole was in the firewall originally and wasn't made by a previous owner.  Any ideas of where to find a correct rubber grommet?  I thought one of the grommets used to plug unused brake line holes in the front inner fenders might work, but it was too small.

[CharlesTurner]

Thanks for the picture.  I feel better knowing that that 2nd hole was in the firewall originally and wasn't made by a previous owner.  Any ideas of where to find a correct rubber grommet?  I thought one of the grommets used to plug unused brake line holes in the front inner fenders might work, but it was too small.

Pretty sure it's the same size used in the trunk floors on top.  Pushes in from the interior of the car.

[drummingrocks]

Thanks!

[midlife]

Hmmm...I have a 66 that came with a 4 speed, and there's only the hole in the firewall for the speedo cable.  The center hump has not been molested and there isn't any hole there for the speedo cable.

[rockhouse66]

Hmmm...I have a 66 that came with a 4 speed, and there's only the hole in the firewall for the speedo cable.  The center hump has not been molested and there isn't any hole there for the speedo cable.

Ditto.

[CharlesTurner]

Well, I have 2 '66 examples with the C4 hole, can anyone provide a pic of an original '66 floor without the hole?

Jan '66 Metuchen/March '66 San Jose (both factory 4 speed cars)

[rockhouse66]

Hmmmm - upon further review, my 9/65 SJ car may have that hole.  Tell me if you agree please.  When I took the car apart, it had a really long speedo cable in it and it was routed through the firewall hole 

[CharlesTurner]

Hmmmm - upon further review, my 9/65 SJ car may have that hole.  Tell me if you agree please.  When I took the car apart, it had a really long speedo cable in it and it was routed through the firewall hole 

The hole we're taking about is further over, right above where the parking brake cable bracket attaches.