Vacuum Gauge Hookup Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Roberty · 06-06-2005, 08:15 PM

How does the FACTORY vacuum gauge hook up? I know that probably all that would have to be done is to run a rubber hose from the vacuum port behind the carb to the gauge but how was it done from GM on trucks that originally had the factory vacuum gauge option?

Also, what was the original code on the glove box door on the trucks so equipped?

Thanks,
Robert

Bob Moore · 06-06-2005, 08:56 PM

The factory set ups I have seen used steel tubing to the vac. spud on the intake manifold on the passenger side behind the carb. Yes there is a little hose to mate but I think if it was all hose it would deteriorate(sp) under the hood. Same size tubing as the vac. advance and trans. modulator. Same size rubber hose for unions.

Roberty · 06-06-2005, 09:00 PM

Thanks for the info Bob. That's what I figured. Now I've got to just find an original hose/tube setup for sale. I haven't seen this repo'ed yet.

Anyone have an original one for sale?

purple gas · 06-07-2005, 10:24 PM

OK, here's a stupid question.. Why does a person need a vacume guage anyways?

Robert1970C20rstbukt · 06-07-2005, 11:05 PM

They let you know if you have a valve-train problem. Like if your camshaft lobes are worn, you won't have much vacuum. Stock engines should have 17 to 25 inches of vacuum I think.

Roberty · 06-07-2005, 11:23 PM

Quote:

Originally Posted by Robert1970C20rstbukt

They let you know if you have a valve-train problem. Like if your camshaft lobes are worn, you won't have much vacuum. Stock engines should have 17 to 25 inches of vacuum I think.

It also lets you get a general idea of fuel economy or lack there-of. Low vacuum = poor fuel economy. The late model cars and trucks that give MPG estimates while you drive are probably based on engine vacuum if I had to guess.

My old Chevelle SS convertable has a vacuum gauge of sorts - it's called a Cowl Induction Hood.

Stomp the go pedal = low vacuum = Cowl Induction pops up on the hood.

Chevy Muscle · 06-08-2005, 10:53 AM

Quote:

Originally Posted by Bob Moore

The factory set ups I have seen used steel tubing to the vac. spud on the intake manifold on the passenger side behind the carb. Yes there is a little hose to mate but I think if it was all hose it would deteriorate(sp) under the hood. Same size tubing as the vac. advance and trans. modulator. Same size rubber hose for unions.

Anyone have a picture of one of these tubes?

06-06-2005, 08:15 PM	#1
Roberty Hot Damn - Here I Am!! Join Date: Feb 2000 Location: Ringgold, Georgia Posts: 726	Vacuum Gauge Hookup Question How does the FACTORY vacuum gauge hook up? I know that probably all that would have to be done is to run a rubber hose from the vacuum port behind the carb to the gauge but how was it done from GM on trucks that originally had the factory vacuum gauge option? Also, what was the original code on the glove box door on the trucks so equipped? Thanks, Robert __________________ My vehicles: '90 Silverado Sport '71 Chevelle SS Convertible '70 C-10 - My Grandfather bought it new - original un-restored Last edited by Roberty; 06-06-2005 at 08:15 PM.

06-06-2005, 08:56 PM	#2
Bob Moore Registered User Join Date: Feb 2004 Location: Tacoma WA Posts: 1,365	No hose The factory set ups I have seen used steel tubing to the vac. spud on the intake manifold on the passenger side behind the carb. Yes there is a little hose to mate but I think if it was all hose it would deteriorate(sp) under the hood. Same size tubing as the vac. advance and trans. modulator. Same size rubber hose for unions. __________________ 67 C-20 LWB, tilt, speed alert, vac, 454, T400 67 C-10 SWB, factory air with more to follow

06-06-2005, 09:00 PM	#3
Roberty Hot Damn - Here I Am!! Join Date: Feb 2000 Location: Ringgold, Georgia Posts: 726	Thanks for the info Bob. That's what I figured. Now I've got to just find an original hose/tube setup for sale. I haven't seen this repo'ed yet. Anyone have an original one for sale? __________________ My vehicles: '90 Silverado Sport '71 Chevelle SS Convertible '70 C-10 - My Grandfather bought it new - original un-restored

06-07-2005, 10:24 PM	#4
purple gas Registered User Join Date: Oct 2004 Location: saskatoon, planet earth Posts: 694	OK, here's a stupid question.. Why does a person need a vacume guage anyways? __________________ I got a bench seat baby, you don't have to sit over there.

06-07-2005, 11:05 PM	#5
Robert1970C20rstbukt Registered User Join Date: Jun 2004 Location: Beeville, Texas Posts: 1,943	They let you know if you have a valve-train problem. Like if your camshaft lobes are worn, you won't have much vacuum. Stock engines should have 17 to 25 inches of vacuum I think. __________________ RJD 1984 Chevrolet C30 welding truck 454/SM465 1977 GMC C15 pickup 350/TH350 1970 Chevrolet C20 pickup 350/TH400 1970 Chevrolet K20 Suburban 454/TH350 1969 GMC 8500 478M V6/5 spd winch truck

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