[crider]

Could someone post up a few pics of the tach wire routing on a 71 bird? I have added rally gauges to my firebird and need to see where the wires run under the hood. Thanks in advance

[70RAlll]

Originally Posted by crider

Could someone post up a few pics of the tach wire routing on a 71 bird? I have added rally gauges to my firebird and need to see where the wires run under the hood. Thanks in advance

It comes through the firewall in a hole just above the main engine compartment wiring harness firewall hook up and routs over behind the brake booster and to the firewall center clip then to the coil..

[JJKJ]

Is there any possible way someone could take a pic of this to show exactly where the harness comes through the firewall? I looked and don't seem to have a hole in the area described in the previous post. I assumed all cars would come pre-drilled for something like the tach wiring.

[SD73]

A piggy back question on this too. Does the fuse holder have an AMP rating printed on it?

[Held for Ransom]

Originally Posted by SD73

A piggy back question on this too. Does the fuse holder have an AMP rating printed on it?

My '74 doesn't.

Originally Posted by crider

Could someone post up a few pics of the tach wire routing on a 71 bird? I have added rally gauges to my firebird and need to see where the wires run under the hood. Thanks in advance

Dens71TA is probably right (I didn't measure the hole size). Diagram is from the '71 Service Manual. Pictures are from two of my '74s.

[Dens71TA]

The cars are NOT pre-drilled for the tach. There is a locating dimple on the firewall for the holesaw. From what I recall, its 1.25" diameter hole. The rubber grommets are reproduced or you can find used one in the junkyard.

[SD73]

Thanky, HfR!

[JJKJ]

Thanks for the info and the pics!

[eaglesan13]

This is a picture of the firewall in my 70 Formula 400, without factory gauges (no tach). I guess one of these dimples would be where the hole would be drilled.

[JJKJ]

Originally Posted by eaglesan13

This is a picture of the firewall in my 70 Formula 400, without factory gauges (no tach). I guess one of these dimples would be where the hole would be drilled.

I located those two dimples as well on my 72. Anyone know which one is correct to center on? I also did some searching today through catalogs and didn't see the grommet listed, at least not as a tach harness grommet in particular. Any info on where one can be obtained? Once I have one, it'll be easy to determine the correct hole size from it.

[Lloyd-TX]

From HfR's illustration and photos, I'd have to say it's the outer of those two dimples.

[70RAlll]

I will post a picture of the correct hole location and size later today. The grommet is the same/similar to the one where the vacuum tubes exit the firewall next to the heater box..I have a 71 TA with the complete engine compartment removed so I can get you a good picture and I will use my dial caliper to measure the holes diameter.I am pretty sure it is 1.25", but will verify for you..

[70RAlll]

Here are pictures of the hole for the tach wire. Plus the measurement on mine was 1.28", so a 1.25" hole saw is what you need. The fuse holder will have a "30AMP" branded into the plastic with black ink/paint in the 30AMP brand. These are not reproduced with the 30AMP script any longer, there is a GM dealer in Texas that has a couple 100 of these using the original GM part number, but they do not have the 30 AMP on it.The AC cars used the same fuse holder on their high fan relay feed at the rear of teh alternator. Only the older NOS ones by this part number have the 30 AMP. I found 4 NOS ones in a dealer in Lousiana last year which is how I found this out..I don't have the part number handy, you can look in an assembly manual to get it and have your local GM dealer to a search for them. They can order from this dealer in TX..

[JJKJ]

Thanks 70RAIII! Now if I can just track down a grommet. I've been through all my catalogs and it seems no one carries any of the firewall grommets with the exception of where the speedo cable goes through.

I also took a look up under the dash to get an idea on where the hole would come through to the inside. It's pretty tight quarters up there above the fuse box where the hole would come through.

[Held for Ransom]

Originally Posted by JJKJ

Thanks 70RAIII! Now if I can just track down a grommet. I've been through all my catalogs and it seems no one carries any of the firewall grommets with the exception of where the speedo cable goes through.

PY doesn't have a picture of the one they sell, so I can't recommend them. Inline Tube, http://www.inlinetube.com/ , does show something (PN INL10756) for $12. Ames also list different ones, but no pictures.

[70RAlll]

someone posted these were available, I have never seen them reproduced.maybe they are. look in the repo companys cataloges. If not, you will have to find a parted out car . Like I said earlier, it is the same plug that is used to the center right near the heater/ac box where the colored vacuum tubes exit the firewall into the engine compartment...

[70RAlll]

Originally Posted by 70RAlll

Here are pictures of the hole for the tach wire. Plus the measurement on mine was 1.28", so a 1.25" hole saw is what you need. The fuse holder will have a "30AMP" branded into the plastic with black ink/paint in the 30AMP brand. These are not reproduced with the 30AMP script any longer, there is a GM dealer in Texas that has a couple 100 of these using the original GM part number, but they do not have the 30 AMP on it.The AC cars used the same fuse holder on their high fan relay feed at the rear of teh alternator. Only the older NOS ones by this part number have the 30 AMP. I found 4 NOS ones in a dealer in Lousiana last year which is how I found this out..I don't have the part number handy, you can look in an assembly manual to get it and have your local GM dealer to a search for them. They can order from this dealer in TX..

I recieved 2 PM's asking for the dealer in TX that has these fuse holders. The GM part number is GM#6287486 and it is Mcginnis Cadillac Hummer Houston TX 281-496-8700 just ask for parts and ask the guy to check and see if he has any of this part number. they showed 49 this morning..

[1973Formula]

Anyone have a picture of the tach wiring harness? I was looking through my harness box and found the correct tach section. However, I am missing the piece between the coil and fuse holder. I would like to see what the whole harness looks like. Also, what wires go where on the instrument panel?

Thanks,