Picture Request: Factory Tach Harness/Vacuum Tubing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tcb-1 · 11-08-2008, 11:04 PM

I need a pic of where the factory tach harness col wire goes through the firewall. my 67-72 assembly book shows the coil wire entering the engine bay close to where the oil pressure tubing comes through. however on a search, someone posted the location was to the right of the main harness connection under the master cylinder.

and......

I'd also really like a pic of the factory vacuum gauge tubing in the engine bay. this will probably only be able to come from the big boys (C-40 and above). I know where it connects to the manifold, but I'd like to know where it enters the cab and if it is coiled like the oil pressure.

Thanks!!!!!

JimKshortstep4x4 · 11-09-2008, 10:09 AM

Here is a pic of the firewall on a 72 with factory tach hole located to the left of the bulkhead connector. Other years could be different.

Jim

badpeanut · 11-09-2008, 11:37 AM

Quote:

Originally Posted by tcb-1

I'd also really like a pic of the factory vacuum gauge tubing in the engine bay. this will probably only be able to come from the big boys (C-40 and above). I know where it connects to the manifold, but I'd like to know where it enters the cab and if it is coiled like the oil pressure.

Was it hard line all the way from the manifold to the gauge or was there some rubber hose also?

tcb-1 · 11-09-2008, 02:12 PM

^^^I'd like to know that as well. was it rubber tubing or hard line like the oil pressure line. my bet it was hard tubing....

thanks for the pic Jim. I read the thread that you had posted that pic before. thanks for the good info!

any other tach or vacuum info out there???

**Already Gone** · 11-09-2008, 02:34 PM

ttt

**jamie72** · 11-09-2008, 05:58 PM

doug all vac gauge clusters i have taken out have been hard line, i got a 70 1/2 ton that the owner had the dealership install a vac in the cluster it also has the hard lines..

tcb-1 · 11-09-2008, 06:08 PM

Thanks Jamie!!! I should have pulled an oil pressure line when I was at the salvage yard yesterday. Darn it!

**jamie72** · 11-09-2008, 08:25 PM

the lines for vacs are bigger like brake lines, or they are from what i have seen.. good luck.

tcb-1 · 11-09-2008, 08:39 PM

just an fyi to all.

I drilled the bulkhead in the exact dimple that Jim had pictured above, and it was perfect. the reproduction tach harness (from Classic Parts) fits the location like a glove. the wiring had the correct length and the coil wire was long enough to run up to the bulkhead gutter, over the engine, and back down to the coil.

a little non adhesive black tape and it looks completely factory.

now on to the vacuum portion of the show......

badpeanut · 11-24-2008, 01:28 AM

Any updates on the vacuum gauge?

tcb-1 · 11-24-2008, 09:11 AM

installed in the cluster (and it loos killer!), but dealing with a vacuum advance issue right now. as soon as I get my stumbling engine problem figured out, I plan on getting pictures up.

badpeanut · 12-10-2008, 09:43 PM

I have two ideas for vacuum gauge "plumbing":

Rubber hose all the way (GM did this on late '70s early '80s GM fullsize car vacuum gauges)
Use a 1/4" compression fitting and flared 1/4" diameter copper tube from the plumbing section of the hardware store

Feedback is appreciated.

re1 · 06-11-2015, 11:54 AM

--------------------------------------------------------------------------------

Any updates on the vacuum gauge?

**Already Gone** · 06-11-2015, 03:16 PM

I haven't installed mine yet but have all the parts and will use a steel line from the fitting on the engine to inside the cab then use rubber line to connect to gauge.

re1 · 06-11-2015, 05:56 PM

Quote:

Originally Posted by Already Gone

I haven't installed mine yet but have all the parts and will use a steel line from the fitting on the engine to inside the cab then use rubber line to connect to gauge.

That sounds like the best way to go,
any pictures would be great.

BROWN 70 · 06-11-2015, 07:47 PM

Hi Guys, I dont have a picture but my 70 GMC has the large vacuum gauge in the center of the dash ( between the speedo and gas gauge) and it has a rubber hose that runs through a gray plastic grommet, then to the side of the QJet. hope thes helps. mike

11-08-2008, 11:04 PM	#1
tcb-1 Nothing to see here..... Join Date: Jun 2007 Location: Shawnee, KS Posts: 4,625	Picture Request: Factory Tach Harness/Vacuum Tubing I need a pic of where the factory tach harness col wire goes through the firewall. my 67-72 assembly book shows the coil wire entering the engine bay close to where the oil pressure tubing comes through. however on a search, someone posted the location was to the right of the main harness connection under the master cylinder. and...... I'd also really like a pic of the factory vacuum gauge tubing in the engine bay. this will probably only be able to come from the big boys (C-40 and above). I know where it connects to the manifold, but I'd like to know where it enters the cab and if it is coiled like the oil pressure. Thanks!!!!! __________________ Doug THANK YOU to our American Soldiers & Veterans - POW MIA "You will NEVER be forgotten". The democracy will cease to exist when you take away from those who are willing to work and give to those who would not. Thomas Jefferson

11-09-2008, 10:09 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: Picture Request: Factory Tach Harness/Vacuum Tubing Here is a pic of the firewall on a 72 with factory tach hole located to the left of the bulkhead connector. Other years could be different. Jim Attached Images __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

11-09-2008, 02:12 PM	#4
tcb-1 Nothing to see here..... Join Date: Jun 2007 Location: Shawnee, KS Posts: 4,625	Re: Picture Request: Factory Tach Harness/Vacuum Tubing ^^^I'd like to know that as well. was it rubber tubing or hard line like the oil pressure line. my bet it was hard tubing.... thanks for the pic Jim. I read the thread that you had posted that pic before. thanks for the good info! any other tach or vacuum info out there??? __________________ Doug THANK YOU to our American Soldiers & Veterans - POW MIA "You will NEVER be forgotten". The democracy will cease to exist when you take away from those who are willing to work and give to those who would not. Thomas Jefferson

11-09-2008, 02:34 PM	#5
Already Gone 70+ ( Old Skool Club ) Join Date: Nov 2003 Location: Saskatoon, Saskatchewan ,Canada Posts: 9,162	Re: Picture Request: Factory Tach Harness/Vacuum Tubing ttt __________________ 1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021

11-09-2008, 05:58 PM	#6
jamie72 Senior Member Join Date: Apr 2000 Location: madison indiana Posts: 3,839	Re: Picture Request: Factory Tach Harness/Vacuum Tubing doug all vac gauge clusters i have taken out have been hard line, i got a 70 1/2 ton that the owner had the dealership install a vac in the cluster it also has the hard lines.. __________________ jamie72 72 BB cheyenne -- Restoration getting started.. member #807 http://www.myspace.com/whitetailobsession www.antlertalk.com

11-09-2008, 06:08 PM	#7
tcb-1 Nothing to see here..... Join Date: Jun 2007 Location: Shawnee, KS Posts: 4,625	Re: Picture Request: Factory Tach Harness/Vacuum Tubing Thanks Jamie!!! I should have pulled an oil pressure line when I was at the salvage yard yesterday. Darn it! __________________ Doug THANK YOU to our American Soldiers & Veterans - POW MIA "You will NEVER be forgotten". The democracy will cease to exist when you take away from those who are willing to work and give to those who would not. Thomas Jefferson

11-09-2008, 08:25 PM	#8
jamie72 Senior Member Join Date: Apr 2000 Location: madison indiana Posts: 3,839	Re: Picture Request: Factory Tach Harness/Vacuum Tubing the lines for vacs are bigger like brake lines, or they are from what i have seen.. good luck. __________________ jamie72 72 BB cheyenne -- Restoration getting started.. member #807 http://www.myspace.com/whitetailobsession www.antlertalk.com

11-09-2008, 08:39 PM	#9
tcb-1 Nothing to see here..... Join Date: Jun 2007 Location: Shawnee, KS Posts: 4,625	Re: Picture Request: Factory Tach Harness/Vacuum Tubing just an fyi to all. I drilled the bulkhead in the exact dimple that Jim had pictured above, and it was perfect. the reproduction tach harness (from Classic Parts) fits the location like a glove. the wiring had the correct length and the coil wire was long enough to run up to the bulkhead gutter, over the engine, and back down to the coil. a little non adhesive black tape and it looks completely factory. now on to the vacuum portion of the show...... __________________ Doug THANK YOU to our American Soldiers & Veterans - POW MIA "You will NEVER be forgotten". The democracy will cease to exist when you take away from those who are willing to work and give to those who would not. Thomas Jefferson

11-24-2008, 01:28 AM	#10
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,760	Re: Picture Request: Factory Tach Harness/Vacuum Tubing Any updates on the vacuum gauge? __________________ '05 Chevy 2500HD 4x4 '72 GMC LWB 4x2 driver '72 Chevy LWB 4x4 plow truck '71 Blazer 4x4 driver '70 GMC LWB trailer

11-24-2008, 09:11 AM	#11
tcb-1 Nothing to see here..... Join Date: Jun 2007 Location: Shawnee, KS Posts: 4,625	Re: Picture Request: Factory Tach Harness/Vacuum Tubing installed in the cluster (and it loos killer!), but dealing with a vacuum advance issue right now. as soon as I get my stumbling engine problem figured out, I plan on getting pictures up. __________________ Doug THANK YOU to our American Soldiers & Veterans - POW MIA "You will NEVER be forgotten". The democracy will cease to exist when you take away from those who are willing to work and give to those who would not. Thomas Jefferson

12-10-2008, 09:43 PM	#12
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,760	Re: Picture Request: Factory Tach Harness/Vacuum Tubing I have two ideas for vacuum gauge "plumbing": Rubber hose all the way (GM did this on late '70s early '80s GM fullsize car vacuum gauges) Use a 1/4" compression fitting and flared 1/4" diameter copper tube from the plumbing section of the hardware store Feedback is appreciated. __________________ '05 Chevy 2500HD 4x4 '72 GMC LWB 4x2 driver '72 Chevy LWB 4x4 plow truck '71 Blazer 4x4 driver '70 GMC LWB trailer

06-11-2015, 11:54 AM	#13
re1 Registered User Join Date: Oct 2005 Location: Metro Vancouver Posts: 444	Re: Picture Request: Factory Tach Harness/Vacuum Tubing -------------------------------------------------------------------------------- Any updates on the vacuum gauge? __________________ 1972 Chevy C10 Custom Deluxe Highlander 1972 Chevy C10 Custom Deluxe Medium Green

06-11-2015, 03:16 PM	#14
Already Gone 70+ ( Old Skool Club ) Join Date: Nov 2003 Location: Saskatoon, Saskatchewan ,Canada Posts: 9,162	Re: Picture Request: Factory Tach Harness/Vacuum Tubing I haven't installed mine yet but have all the parts and will use a steel line from the fitting on the engine to inside the cab then use rubber line to connect to gauge. __________________ 1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021

06-11-2015, 07:47 PM	#16
BROWN 70 Registered User Join Date: Aug 2010 Location: central oregon Posts: 166	Re: Picture Request: Factory Tach Harness/Vacuum Tubing Hi Guys, I dont have a picture but my 70 GMC has the large vacuum gauge in the center of the dash ( between the speedo and gas gauge) and it has a rubber hose that runs through a gray plastic grommet, then to the side of the QJet. hope thes helps. mike

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