Tach cluster

[LockDoc]

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I usually hang out over on the ’67-’72 board but I was doing some research on here about the tach/fuel combo instrument panels. I found most of the information I was looking for but I was wondering if the cluster was the same for the big trucks and pickups. The air pressure gauge has two lines on the back and it looks like it has two needles, one White and one Orange??? I was also wondering if there is any differences in the doors. The width measurements appear to be the same but wanted to make sure there wasn’t any shape differences that I’m not seeing. The truck is an ’86 70 series. Thanks for any help on this.

LockDoc

[doubleclucker]

The medium trucks 67-72 and 73-87 are very similar and clusters will fit with some wire/pin shuffle . If you find a lower gvwr with hydaulic brakes it may have a optional Vacuum gauge instead .
Note: (Tachometers are usually engine specific).
I borrowed these pics off other threads on here.

[LockDoc]

Originally Posted by doubleclucker

The medium trucks 67-72 and 73-87 are very similar and clusters will fit with some wire/pin shuffle . If you find a lower gvwr with hydaulic brakes it may have a optional Vacuum gauge instead .
Note: (Tachometers are usually engine specific).
I borrowed these pics off other threads on here.

Thanks. I have a couple of the '67-'72 tach dashes. This truck is over at the salvage yard a couple of miles from me. It has a Cat V-8 in it and it is a running and driving truck but they are going to crush it because it doesn't have a title and he doesn't want to mess with it. The doors are really nice on it and that is why I wondered about them. The cluster in it has an air pressure gauge where the Vac gauge is in your picture.

LockDoc

[Jonboy]

Check the lower front corner of the doors, Leon. I am not sure if they are clearance there a little bit or not. They should have a 90 degree corner on them for light duty trucks. inner workings are the same I believe.

[DBLSPRT68]

GET THAT CLUSTER!!!!!!!!!!! You can sell it to someone $$$. I had an 84 C40 dash cluster in my old 83 C20. It is a plug and play cluster for 78-87 chevy trucks. I say 78 because, before then; there were differences in the wiring. I actually removed the air guage and put the factory clock in the hole. Everything worked perfect for several years. Then pulled it and sold the truck. It will go in my Suburban next.

[LockDoc]

Originally Posted by Jonboy

Check the lower front corner of the doors, Leon. I am not sure if they are clearance there a little bit or not. They should have a 90 degree corner on them for light duty trucks. inner workings are the same I believe.

Yes, the corners are square. Thanks.

Originally Posted by DBLSPRT68

GET THAT CLUSTER!!!!!!!!!!! You can sell it to someone $$$. I had an 84 C40 dash cluster in my old 83 C20. It is a plug and play cluster for 78-87 chevy trucks. I say 78 because, before then; there were differences in the wiring. I actually removed the air guage and put the factory clock in the hole. Everything worked perfect for several years. Then pulled it and sold the truck. It will go in my Suburban next.

I am headed over there now. It also has factory looking speakers in both back corners of the cab up by the seam. They fit the curve of the cab perfectly. Thanks.

LockDoc

[ray_mcavoy]

Originally Posted by DBLSPRT68

GET THAT CLUSTER!!!!!!!!!!! You can sell it to someone $$$. I had an 84 C40 dash cluster in my old 83 C20. It is a plug and play cluster for 78-87 chevy trucks. I say 78 because, before then; there were differences in the wiring. I actually removed the air guage and put the factory clock in the hole. Everything worked perfect for several years. Then pulled it and sold the truck. It will go in my Suburban next.

I agree. That 86 C70 cluster should be a direct swap into a 78-87 pickup, Suburban, or full-size Blazer/Jimmy that was originally equipped with a full gauge cluster. It might have some different warning/indicator lights at the bottom of the speedometer than what would be found in a pickup truck but those are easy to swap the little colored lenses if necessary. It would require changes to the wiring if used in an earlier year (73-77) pickup or any 73-87 that was originally equipped with a warning light cluster instead of gauges.

The air pressure gauges are probably quite popular with folks using air ride suspensions or like DBLSPRT68 said, can be swapped for a clock. That's something you can't do with the stock 10-35 series tach clusters because the small fuel gauge is located in that lower/left corner instead of in the bottom of the tach.

When you pull the cluster, get the 3-wire harness that plugs into the back of the tach too. The other ends should just plug into the fusebox and ground buss near the lower corner of the dash (near where a pickup parking brake pedal would be). And one wire goes through a grommet in the firewall. With a diesel engine, these tachs operated off a magnetic sensor that reads off the flywheel teeth. I think they can be converted for use with a gas engine by changing the calibration resistor on the circuit board.

[LockDoc]

Originally Posted by ray_mcavoy

I agree. That 86 C70 cluster should be a direct swap into a 78-87 pickup, Suburban, or full-size Blazer/Jimmy that was originally equipped with a full gauge cluster. It might have some different warning/indicator lights at the bottom of the speedometer than what would be found in a pickup truck but those are easy to swap the little colored lenses if necessary. It would require changes to the wiring if used in an earlier year (73-77) pickup or any 73-87 that was originally equipped with a warning light cluster instead of gauges.

The air pressure gauges are probably quite popular with folks using air ride suspensions or like DBLSPRT68 said, can be swapped for a clock. That's something you can't do with the stock 10-35 series tach clusters because the small fuel gauge is located in that lower/left corner instead of in the bottom of the tach.

When you pull the cluster, get the 3-wire harness that plugs into the back of the tach too. The other ends should just plug into the fusebox and ground buss near the lower corner of the dash (near where a pickup parking brake pedal would be). And one wire goes through a grommet in the firewall. With a diesel engine, these tachs operated off a magnetic sensor that reads off the flywheel teeth. I think they can be converted for use with a gas engine by changing the calibration resistor on the circuit board.

Thanks for the info Ray. I didn't have much time to remove parts from it so I cut the tach wire as far back as I could reach, about a foot. So I got the cluster, AM/FM stereo radio, speaker, and the rear speakers & all wiring, sun visors, both complete doors, heater control, Ignition switch with key, dome light, and seat belts. All of the parts are in pretty good shape.

Thanks everyone for your help.

LockDoc

[LockDoc]

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Wondering if anyone can confirm if these speakers are factory or not. They were in the rear cab corners with the top even with the body/roof seam. They fit the corners perfectly at the top and bottom and have speakers in them that are the same as the in dash speaker. The Blue connector was plugged into a separate receptacle on the back of the radio than the in dash speaker. The loom with no tape ran under the sill plate and to a clip behind the "B" pillar. The taped loom ran from there to each speaker. The radio is listed on the SPID as a "Del AM/FM Stereo".

Thanks for any help on this.

LockDoc

[ray_mcavoy]

Originally Posted by LockDoc

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Wondering if anyone can confirm if these speakers are factory or not ...

LockDoc

The ones I'm familiar with have stamped steel mounting brackets (both factory-installed and dealer-installed) ... I don't think I've ever seen a set with molded plastic brackets like that. However, they sure do look like factory pieces.

The radio/speaker connectors look the same as those used with most 78-up GM radios. Although it looks like there are only 2 wires (instead of 4) in that blue connector for the rear speakers. They must have been using a front/rear (instead of left/right) stereo separation setup. With the front dash speaker on one channel and the rear speakers on the other. I know GM did that in some vehicles.

Originally Posted by LockDoc

Thanks for the info Ray. I didn't have much time to remove parts from it so I cut the tach wire as far back as I could reach, about a foot.

You're welcome. That should be okay. The connections are marked on the back of the tach. Having the whole harness just makes it easier to plug-n-play.

[motornut]

neat find
I've only seen smooth covers,but the texture might match some bezels
86 i doubt they would be still useing chassis grounded speakers...
are the speakers gm stock?
yes stereo front to back was common,more in work trucks i find
I powered my tach from the cluster power,not through firewall as it would be stock

[Irish1941]

Out of a medium duty with a Cat?
Hmm...wonder if it's a 6 cyl tach or diesel specific tach? Does it top out at 4k?

[LockDoc]

Originally Posted by motornut

neat find
I've only seen smooth covers,but the texture might match some bezels
86 i doubt they would be still useing chassis grounded speakers...
are the speakers gm stock?
yes stereo front to back was common,more in work trucks i find
I powered my tach from the cluster power,not through firewall as it would be stock

Yes, the speakers are GM stock type. Thanks

Originally Posted by Irish1941

Out of a medium duty with a Cat?
Hmm...wonder if it's a 6 cyl tach or diesel specific tach? Does it top out at 4k?

Thanks guys. Here is a picture of the cluster. It has a lot of dust under the clear cover. The cab was just full of corn cob chaff and dust...

I just noticed it has a 100 psi oil pressure gauge. It also shows 335,460 miles...

LockDoc

[Irish1941]

Yep, diesel tach. I missed the Cat V8 part.
Pretty cool. Don't see many of them.
That speedo is rare too. Only big trucks got the 7 digit ODs before 1990 electric speedos in V,R trucks.
Only downside with that tach with fuel gauge in it is that it won't work for 4wd trucks.
Here is mine in my '89 Blazer. Came from a '80s K30.

[LockDoc]

Originally Posted by Irish1941

Yep, diesel tach. I missed the Cat V8 part.
Pretty cool. Don't see many of them.
That speedo is rare too. Only big trucks got the 7 digit ODs before 1990 electric speedos in V,R trucks.
Only downside with that tach with fuel gauge in it is that it won't work for 4wd trucks.
Here is mine in my '89 Blazer. Came from a '80s K30.

Thanks Irish.

LockDoc

[Oldriginal86]

Hey Doc, did the donor truck have the original dash pad? As I recall they were made from some type of pressed cardboard. Good thing is I never saw one of those crack. Would love to find one in decent shape. Water damaged them pretty bad.

[LockDoc]

Originally Posted by Oldriginal86

Hey Doc, did the donor truck have the original dash pad? As I recall they were made from some type of pressed cardboard. Good thing is I never saw one of those crack. Would love to find one in decent shape. Water damaged them pretty bad.

This one was plastic. It was cracked at the speaker area and the defroster on the drivers side. Better shape than most...

LockDoc