tell me about tach dashes..Big truck ones - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Custom 68 · 08-22-2003, 09:35 PM

Hey all I looked at a tach dash with the air pressure gage and warning lights for the air. I really dont know much about these it had the printed circuit board and lookd to be in good shape. The back of the tach has 2 wires one for positive and one to dist. is this easy to hook up? will my plug to my gage dash just plug into this then just run the 2 wires like it says to the tach?
Thanks
Dave
oh yea are these more or less valuable than a "standard" tach dash?

Huck · 08-22-2003, 09:40 PM

They are a direct swap if you have the later model dash with the oil/amp guages but no tach. The wiring is simple. A good working tach dash goes for about $150. + up depending on condition. The air pressure gauge is often used by guys running air shocks or air bags to monitor the air pressure. They also came with a vacuum guage in that spot which is even more interesting. The common variation has just a blank in the spot where the air pressure gauge is located. Wiring harnesses, lenses, and the rear plastic wiring are all availabe as is the bezel and the rest of the gauges.

Rod · 08-22-2003, 09:51 PM

Change the gas guage and the bezel and it will work...... brown wire to distributor negative side and red wire to unfused on fuse box. Plug from your full guage harness will plug in... dont forget to hook up the oil line.... 5/16 wrench. Rod

Tx Firefighter · 08-22-2003, 10:14 PM

What about all the little dump trucks that had 292 6 cylinders in them? Did they use a different tach than the 8 cylinder trucks. I know for a fact that some c50 and c60 dump trucks had 6s, because that's where mine came from. Don't know if they had tachs though, because the trucks were stripped of the dashes when I got there.

Anybody seen one for a 6 cylinder?

Custom 68 · 08-22-2003, 10:27 PM

good question TX I didnt see any marks on this indicating it was for a V8 the guy told me it was but I wasnt sure.
Thanks for all the info guys!

**jamie72** · 08-22-2003, 10:55 PM

from what i have seen thou,you need to change out he plastic outer bezel for our trucks,the bigger trucks don`t have the deep cutout for the sterring coulm,in our trucks it will make it set too lower.
nice find good luck withe it.
jamie

sameyrasmea72 · 08-22-2003, 11:59 PM

I have been told that those big trucks have two different tachs, but the 2nd has a reading of an additional 1000 RPM's so its should be easy to spot the difference. As far as I know the other should work out of a 6 or 8.

FYI- If you spot one of those old big trucks and it has a @4x8 chrome vent looking thing on the drivers fender ( easy to spot from a distance) I could nearly guarrentee it has a 427ci and a correct tach. Or did at one time. This might be common knowledge, I just have not been here long enough to readabout it yet.
( just so someone doesn't have to point it out to me again)

palallin · 08-23-2003, 12:11 AM

I have the guts out of a tach dash that must have come from a big truck orginally, as it has the pressure gauge. It will be plumbed into my air tank once I get my home-grown Ready-air system mounted (for tires, not air bags). Handy as heck and quasi-original, too. What more could ya want?

junkyardjohn · 08-23-2003, 11:54 AM

BIG TRUCK TACHS ARE A FIND. THE GAS GAUGES ARE THE SAME, & WILL WORK FINE, EXCEPT THE IDIOT LITES ARE DIFFERENT. (I THINK IT SAYS TANDEM LOCK, WHERE IT SHOULD SAY BRAKE) THE BEZEL WILL EITHER HAVE TO BE CHANGED, OR THE SLOT FOR THE COLLUMB SHAFT WILL HAVE TO BE CUT OUT?(MADE DEEPER).
THERE ARE THREE DIFFERENT TACHS. ONE FOR SIX CYL.S ONE FOR EIGHT CYL.S (NO PHYSICAL DIFFERENCE, BUT THERE SHOULD BE A STICKER, OR MARKING ON THE BACK OF THE TACH HOUSING.) (IF YOUR LUCKY) & ONE FOR DIESELS (THEY'RE EASY TO SPOT CAUSE THEY ONLY GO UP TO 4000 RPMS & GAS ENG. TACHS GO UP TO 5000 RPMS. HOPE THIS HELPS. JOHN

(BY THE WAY..... THE LAST TACH DASH THE I SOLD ON EBAY (WITH A NEW BEZEL, & EVERTHING IN GREAT SHAPE) SOLD FOR $325

LudwigTheMad · 08-23-2003, 12:20 PM

this whole thread seems kinda...tachy to me.....hehehehehehehheaehhahehaehahehahehaheheeee

Longhorn Man · 08-23-2003, 09:16 PM

LOL ludwigs!
The bezel diffirance can be seen in this picture.

**1970cstblazer** · 08-23-2003, 09:58 PM

Oil pressure gauges were either 60 lb or 80 lb units with the big trucks usually using the 80.

Rod · 08-24-2003, 08:28 AM

When checking out tach dashes at swap meets a stuff look at the gas guage.... it will say tandem lock as Junkyardjohn said and the other side of the guage will say overspeed. All this will tell you is that its probably from a big truck... all the stuff is good for swapping into a light duty truck though.

Custom 68 · 08-24-2003, 02:21 PM

Thanks guys for all the great info. It did have all the warning lights just like you said Rod. I may call him and see if I can get it. He has a bunch of other stuff I will go look at next week.
Thanks
Dave

boraxman · 08-24-2003, 03:37 PM

Quote:

Originally posted by junkyardjohn

BIG TRUCK TACHS ARE A FIND. THE GAS GAUGES ARE THE SAME, & WILL WORK FINE, EXCEPT THE IDIOT LITES ARE DIFFERENT. (I THINK IT SAYS TANDEM LOCK, WHERE IT SHOULD SAY BRAKE) THE BEZEL WILL EITHER HAVE TO BE CHANGED, OR THE SLOT FOR THE COLLUMB SHAFT WILL HAVE TO BE CUT OUT?(MADE DEEPER).
THERE ARE THREE DIFFERENT TACHS. ONE FOR SIX CYL.S ONE FOR EIGHT CYL.S (NO PHYSICAL DIFFERENCE, BUT THERE SHOULD BE A STICKER, OR MARKING ON THE BACK OF THE TACH HOUSING.) (IF YOUR LUCKY) & ONE FOR DIESELS (THEY'RE EASY TO SPOT CAUSE THEY ONLY GO UP TO 4000 RPMS & GAS ENG. TACHS GO UP TO 5000 RPMS. HOPE THIS HELPS. JOHN

(BY THE WAY..... THE LAST TACH DASH THE I SOLD ON EBAY (WITH A NEW BEZEL, & EVERTHING IN GREAT SHAPE) SOLD FOR $325

Thats funny, before I bought my brothers truck a guy at a car show offered him $600 for his tach. Im thinking he should have sold it.

junkyardjohn · 08-24-2003, 04:54 PM

YEP------ HE SHOULD HAVE SOLD IT, CONSIDERING YOU CAN GET A BRAND NEW ONE (WITH NEW AS COMPARED TO 31-35 YEAR OLD GAGES) FOR $450

**1970cstblazer** · 08-25-2003, 09:16 AM

A whole cluster on E-Bay with new repro bezel and repro tach is only $240.

E-Bay cluster

junkyardjohn · 08-25-2003, 10:17 AM

THAT IS AN AUCTION. PEOPLE BID ON STUFF, & THE PRICE GOES UP ACCORDINGLY. IT (THE BIDDING) STARTS AT $240.

Quote:

YEP------ HE SHOULD HAVE SOLD IT, CONSIDERING YOU CAN GET A BRAND NEW ONE (WITH NEW AS COMPARED TO 31-35 YEAR OLD GAGES) FOR $450

THE KEY WORD HERE IS BRAND NEW!!
THE TRUCK SHOP IN ORANGE CALIFORNIA SELLS ALL NEW CLUSTERS, WITH A TACH & NO VACUUM GAUGE FOR $447.00.
THESE ARE ALL BRAND SPANKIN NEW GAUGES & NOT JUST PAINTED NEEDLES & A SPEEDO WITH THE MILES RESET TO ZERO.

**1970cstblazer** · 08-25-2003, 11:06 AM

How is the quality of the brand new gauges, and speedometer?

Also is the speedo a 1967-70 style or 1971-72 style?

N2Clsx · 12-18-2003, 06:49 PM

Hi everyone,
What is the tamden lock light for? Mine went on today but I dont know why. Its my wifes '72 blazer. Thanks

Tx Firefighter · 12-18-2003, 07:08 PM

tandem lock was for large trucks with tandem axles.

Obviously, your wife's Blazer has a big truck dash in it. Who knows what the light is indicating in your case, but I absolutely guarantee it's not tandem axle lock.

**too much stuff** · 12-18-2003, 07:21 PM

Interesting stuff... had to check one of mine out. The fuel gauge lights are "tandem lock" and "low vacuum" And the tandem lock light is in the same spot as "brake" on a pick-up.

67sss · 12-19-2003, 12:13 AM

Mine says this on the back, don't they all say 8on them if they're used for v-8, and nothing on them if they're used for something else?

67sss · 12-19-2003, 12:21 AM

N E body have one to sell to fill the M T spot on my dash..

N2Clsx · 12-22-2003, 06:41 PM

If the brake light comes on, what is it indicate?

08-22-2003, 09:35 PM	#1
Custom 68 Registered User Join Date: Nov 2001 Location: Springfield, MO Posts: 2,944	tell me about tach dashes..Big truck ones Hey all I looked at a tach dash with the air pressure gage and warning lights for the air. I really dont know much about these it had the printed circuit board and lookd to be in good shape. The back of the tach has 2 wires one for positive and one to dist. is this easy to hook up? will my plug to my gage dash just plug into this then just run the 2 wires like it says to the tach? Thanks Dave oh yea are these more or less valuable than a "standard" tach dash? __________________ Dave 1968 Custom Chevy with turbo charged 5.3 gen III 4l80e swap 1967-71 GMC 3/4 ton long step 4x4 (not sure what year exactly?) "A good friend will bail you out of jail...but a true friend will be sitting next to you saying "that was frekin awesome". "If it doesn't fit force it...If it breaks then it needed to be replaced anyway!"

08-22-2003, 09:51 PM	#3
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	Change the gas guage and the bezel and it will work...... brown wire to distributor negative side and red wire to unfused on fuse box. Plug from your full guage harness will plug in... dont forget to hook up the oil line.... 5/16 wrench. Rod __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

08-22-2003, 10:14 PM	#4
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	What about all the little dump trucks that had 292 6 cylinders in them? Did they use a different tach than the 8 cylinder trucks. I know for a fact that some c50 and c60 dump trucks had 6s, because that's where mine came from. Don't know if they had tachs though, because the trucks were stripped of the dashes when I got there. Anybody seen one for a 6 cylinder? __________________ I'm on the Instagram- @Gearhead_Kevin

08-22-2003, 10:27 PM	#5
Custom 68 Registered User Join Date: Nov 2001 Location: Springfield, MO Posts: 2,944	good question TX I didnt see any marks on this indicating it was for a V8 the guy told me it was but I wasnt sure. Thanks for all the info guys! __________________ Dave 1968 Custom Chevy with turbo charged 5.3 gen III 4l80e swap 1967-71 GMC 3/4 ton long step 4x4 (not sure what year exactly?) "A good friend will bail you out of jail...but a true friend will be sitting next to you saying "that was frekin awesome". "If it doesn't fit force it...If it breaks then it needed to be replaced anyway!"

08-22-2003, 10:55 PM	#6
jamie72 Senior Member Join Date: Apr 2000 Location: madison indiana Posts: 3,839	from what i have seen thou,you need to change out he plastic outer bezel for our trucks,the bigger trucks don`t have the deep cutout for the sterring coulm,in our trucks it will make it set too lower. nice find good luck withe it. jamie __________________ jamie72 72 BB cheyenne -- Restoration getting started.. member #807 http://www.myspace.com/whitetailobsession www.antlertalk.com

08-22-2003, 09:40 PM	#2
Huck Senior Member Join Date: Jun 2001 Location: Shelbyville, KY Posts: 3,261	They are a direct swap if you have the later model dash with the oil/amp guages but no tach. The wiring is simple. A good working tach dash goes for about $150. + up depending on condition. The air pressure gauge is often used by guys running air shocks or air bags to monitor the air pressure. They also came with a vacuum guage in that spot which is even more interesting. The common variation has just a blank in the spot where the air pressure gauge is located. Wiring harnesses, lenses, and the rear plastic wiring are all availabe as is the bezel and the rest of the gauges.

08-22-2003, 11:59 PM	#7
sameyrasmea72 Senior Member Join Date: Aug 2003 Location: Lubbock, Texas Posts: 2,443	I have been told that those big trucks have two different tachs, but the 2nd has a reading of an additional 1000 RPM's so its should be easy to spot the difference. As far as I know the other should work out of a 6 or 8. FYI- If you spot one of those old big trucks and it has a @4x8 chrome vent looking thing on the drivers fender ( easy to spot from a distance) I could nearly guarrentee it has a 427ci and a correct tach. Or did at one time. This might be common knowledge, I just have not been here long enough to readabout it yet. ( just so someone doesn't have to point it out to me again)

08-23-2003, 12:11 AM	#8
palallin Registered User Join Date: Jul 2002 Location: St. James, MO Posts: 1,238	I have the guts out of a tach dash that must have come from a big truck orginally, as it has the pressure gauge. It will be plumbed into my air tank once I get my home-grown Ready-air system mounted (for tires, not air bags). Handy as heck and quasi-original, too. What more could ya want? __________________ '69 Longstep K-10: 327/SM465/T-221/Closed Knuckle Dana44/12-bolt.

08-23-2003, 11:54 AM	#9
junkyardjohn Registered User Join Date: Aug 2001 Location: SOMERSET KY. Posts: 6,425	BIG TRUCK TACHS ARE A FIND. THE GAS GAUGES ARE THE SAME, & WILL WORK FINE, EXCEPT THE IDIOT LITES ARE DIFFERENT. (I THINK IT SAYS TANDEM LOCK, WHERE IT SHOULD SAY BRAKE) THE BEZEL WILL EITHER HAVE TO BE CHANGED, OR THE SLOT FOR THE COLLUMB SHAFT WILL HAVE TO BE CUT OUT?(MADE DEEPER). THERE ARE THREE DIFFERENT TACHS. ONE FOR SIX CYL.S ONE FOR EIGHT CYL.S (NO PHYSICAL DIFFERENCE, BUT THERE SHOULD BE A STICKER, OR MARKING ON THE BACK OF THE TACH HOUSING.) (IF YOUR LUCKY) & ONE FOR DIESELS (THEY'RE EASY TO SPOT CAUSE THEY ONLY GO UP TO 4000 RPMS & GAS ENG. TACHS GO UP TO 5000 RPMS. HOPE THIS HELPS. JOHN (BY THE WAY..... THE LAST TACH DASH THE I SOLD ON EBAY (WITH A NEW BEZEL, & EVERTHING IN GREAT SHAPE) SOLD FOR $325 __________________ junkyardjohn 69 1 TON TOW TRUCK // 84 4WD CUCV BLAZER// 85 1 TON 4WD STAKE TRUCK// 86 M1031 5/4 TON 4WD CUCV// ALOT OF OLD TRUCKS FOR ONE OLD MAN TO DRIVE. THERES ROOM FOR ALL OF GODS CREATURES RIGHT NEXT TO MY MASHED POTATOES// LIFE MEMBER OF P.E.T.A (PEOPLE EATING TASTY ANIMALS) DON'T RENT U-HAUL ALWAYS TELL THE TRUTH IT WILL AMAZE PART OF THE PEOPLE & ASTONISH THE REST Last edited by junkyardjohn; 08-23-2003 at 11:59 AM.

08-23-2003, 12:20 PM	#10
LudwigTheMad Registered User Join Date: May 2000 Location: Ramona, CA Posts: 2,033	this whole thread seems kinda...tachy to me.....hehehehehehehheaehhahehaehahehahehaheheeee __________________ That's right, I'm back in the game again. No it's not pink..... 1972 Blue and White Suburban.

08-23-2003, 09:16 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	LOL ludwigs! The bezel diffirance can be seen in this picture. Attached Images

08-23-2003, 09:58 PM	#12
1970cstblazer All stock and staying that way Join Date: Jul 2003 Location: Elkland, PA Posts: 2,076	Oil pressure gauges were either 60 lb or 80 lb units with the big trucks usually using the 80.

08-24-2003, 08:28 AM	#13
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	When checking out tach dashes at swap meets a stuff look at the gas guage.... it will say tandem lock as Junkyardjohn said and the other side of the guage will say overspeed. All this will tell you is that its probably from a big truck... all the stuff is good for swapping into a light duty truck though. __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

08-24-2003, 02:21 PM	#14
Custom 68 Registered User Join Date: Nov 2001 Location: Springfield, MO Posts: 2,944	Thanks guys for all the great info. It did have all the warning lights just like you said Rod. I may call him and see if I can get it. He has a bunch of other stuff I will go look at next week. Thanks Dave __________________ Dave 1968 Custom Chevy with turbo charged 5.3 gen III 4l80e swap 1967-71 GMC 3/4 ton long step 4x4 (not sure what year exactly?) "A good friend will bail you out of jail...but a true friend will be sitting next to you saying "that was frekin awesome". "If it doesn't fit force it...If it breaks then it needed to be replaced anyway!"

08-24-2003, 04:54 PM	#16
junkyardjohn Registered User Join Date: Aug 2001 Location: SOMERSET KY. Posts: 6,425	YEP------ HE SHOULD HAVE SOLD IT, CONSIDERING YOU CAN GET A BRAND NEW ONE (WITH NEW AS COMPARED TO 31-35 YEAR OLD GAGES) FOR $450 __________________ junkyardjohn 69 1 TON TOW TRUCK // 84 4WD CUCV BLAZER// 85 1 TON 4WD STAKE TRUCK// 86 M1031 5/4 TON 4WD CUCV// ALOT OF OLD TRUCKS FOR ONE OLD MAN TO DRIVE. THERES ROOM FOR ALL OF GODS CREATURES RIGHT NEXT TO MY MASHED POTATOES// LIFE MEMBER OF P.E.T.A (PEOPLE EATING TASTY ANIMALS) DON'T RENT U-HAUL ALWAYS TELL THE TRUTH IT WILL AMAZE PART OF THE PEOPLE & ASTONISH THE REST



Register or Log In To remove these advertisements.

08-25-2003, 09:16 AM	#17
1970cstblazer All stock and staying that way Join Date: Jul 2003 Location: Elkland, PA Posts: 2,076	A whole cluster on E-Bay with new repro bezel and repro tach is only $240. E-Bay cluster

08-25-2003, 11:06 AM	#19
1970cstblazer All stock and staying that way Join Date: Jul 2003 Location: Elkland, PA Posts: 2,076	How is the quality of the brand new gauges, and speedometer? Also is the speedo a 1967-70 style or 1971-72 style?

12-18-2003, 06:49 PM	#20
N2Clsx Registered User Join Date: Jun 2000 Location: San Dimas CA Posts: 43	Hi everyone, What is the tamden lock light for? Mine went on today but I dont know why. Its my wifes '72 blazer. Thanks

12-18-2003, 07:08 PM	#21
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	tandem lock was for large trucks with tandem axles. Obviously, your wife's Blazer has a big truck dash in it. Who knows what the light is indicating in your case, but I absolutely guarantee it's not tandem axle lock. __________________ I'm on the Instagram- @Gearhead_Kevin

12-18-2003, 07:21 PM	#22
too much stuff Roadtrip! Join Date: Feb 2003 Location: Grand Rapids MN Posts: 13,852	Interesting stuff... had to check one of mine out. The fuel gauge lights are "tandem lock" and "low vacuum" And the tandem lock light is in the same spot as "brake" on a pick-up.

12-19-2003, 12:13 AM	#23
67sss Registered User Join Date: Nov 2002 Location: Mt. Vernon, WA.. Posts: 2,326	tack dash Mine says this on the back, don't they all say 8on them if they're used for v-8, and nothing on them if they're used for something else? Attached Images

12-19-2003, 12:21 AM	#24
67sss Registered User Join Date: Nov 2002 Location: Mt. Vernon, WA.. Posts: 2,326	vacuum guage N E body have one to sell to fill the M T spot on my dash.. Attached Images

12-22-2003, 06:41 PM	#25
N2Clsx Registered User Join Date: Jun 2000 Location: San Dimas CA Posts: 43	If the brake light comes on, what is it indicate?

Register or Log In To remove these advertisements.