in dash tach

[kpmunt]

I recently purchased a 86 Stepside 4X4, 350, AT. I presume that there were in dash tachs available in the cluster. If so what needs to be done to swap one in for the existing cluster? Does it require a different harness other than the lead to the distributor?

[72chevyLWB]

The tach's for the 73-80 you can find around every once in a while. I heard that 81 was the last year for the tach's in trucks. Not totally for sure though. I just found a factory tach in an 81 2 ton truck.Not for sale though.The harness should plug right in and you would have to run the wire for the tach.

[crossy]

*THIS IS A COPY OF THE TEXT I WRITE WHEN I SELL ONE *

,PLEASE READ ON FOR PROPER APPLICATION.
This is one of those items that is commonly mis-advertised as
73-87 when in fact there are several differences in each unit The first
thing to keep in mind is that GM did not offer a Tach as an option after
1981 in light trucks .I have found Canadian units that were supposedly from Mid 80's
trucks/blazers but the speedo is in KmH .It would be easy to install a US MPH
speedo to it.There were 6 cyl. and 8 cyl. models available and a 6 cyl. one
is going to read high in a V-8 application. 95% are probably V-8's. Try to
know it works before you buy it. I have been TOLD that the 73-75 units are
NOT serviceable if they are bad, and keep in mind that ANY service will
probably set you back $125+ . The Light trucks were only offered with a
5,000 RPM tach. The tach is easy to wire, but getting at least a short
piece of the factory pigtail to the back of it is nice to have, But not a
necessity. If you look close at the back of the tach it will tell you where
the wires go. many people don't know that there was a 'filter', that looks like a condenser, installed in many years of the factory wiring for radio interference reasons.It was mounted on the firewall behind the distributor. this is not a necessity .speaking of distributors it does not matter if you have and old point ignition or HEI the tach still works.MOST common ones will work in 78-84 for sure as pretty much a
plug in and go unit. It is possible to work on 1985 and 1986 models
depending on what you have still have in the way of the factory computer
[I.E.= if you have removed the factory feedback carb And ESC distributor,
Etc. and DON'T need feedback then it will be fine]. As far as pickups go it
will not work on an 87 and will not work on Blazers and Burbs from 1987 to
1991 because of feedback needed for the factory EFI computer(ECM). Agian it can and at least one will be made by me to sell.The 1973
to 1975 models used an AMP gauge instead of the VOLT gauge and this can
cause major wiring problems (meltdown) if installed in later trucks equipped
for VOLT gauge or vice-versa. The 1976-77 used the volt gauge but had a
mechanical oil pressure gauge and creates a two year only dilemma of sorts.
If you find a 1976 or 77 unit with the VOLT gauge and the MECH. Oil pressure
then it can be used in 78-up models by converting yours to mechanical, and
actually better, oil pressure gauge. The only thing to keep in mind here is
to get at least a little piece of the factory oil line and fitting that was
on the back of the gauge. I say this because the factory gauge has a unique
type of ferrule and fitting on the back of the gauge that is good to save
and reuse. I have made aftermarket lines/fittings work but have also had
them blow off the back and make one heck of a mess. The factory used a
copper oil pressure line and I prefer that to plastic. Keep in mind that
there were also several variations of needle colors and the type of
lettering/numbers on the gauges. Mixing and matching gauges can create a
weird looking unit. The big trucks ,like C-60's are easily identified by a
tiny fuel gauge UNDER the tach and anything from a blank to air pressure
gauge where the clock option goes in a pickup dash. Some only had 4,000
RPM tachs also.They can be made to work but offer there own unique problems. DAVE

AND I AM STILL LEARNING AFTER 15+ YEARS AT THESE TRUCKS


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with all the rocks that I turn over I should be finding more than slugs!


[This message has been edited by crossy (edited 01-06-2002).]

[kpmunt]

Thanks guys.

[DBLSPRT68]

Crossy, I have one of those (c-60?) tach clusters (5000 rpm) with the small gas gauge and a vac on the side. It has a volt gauge and the mechanical oil press. I wanted to put it in my 82 3/4 or 83 1/2 truck. Both of my trucks have dual tanks. You stated they can be made to work but have there own unique problems. Could you let me know what I will need to do, besides what you said about oil pressure? Thanks, David

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new truck: 1983 silverado c-10 2wd lwb every option 305/th350 1982 3/4 LWB CHEVY 350-TH400-2WD W/89 BURBAN FRONT. TOYOTA CELICA DAILY DRIVER. PROJECT:1965 BEL AIR 2-DOOR.
Southaven, MS

[gchemist]

I have a in dash digital tach.
http://www.geocities.com/abetterchemist/cab.html

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Gerardo
1983 Custom Truck
TX Plates: "BAD BOW"
http://www.geocities.com/abetterchemist/

[Chevyman69]

There is a difference in the heavier trucks as well c60's and what not in that there is no red line. Those engines are all governed and the tach goes to 5 grand but has no markings. I have a neighbor with an 81/82 3/4 ton 4x4 wreck that has the 82 up style guages and a tach with a redline. I have seen a few later versions 84/85 with factory tachs as well. I think I saw an 87 once that had a tach and a TBI 350 that looked like all the previous ones but did not get a chance to talk to him on how he did the swap or if he got it that way, and btw I am from Canada so maybe that is a difference there.

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69 CST 10, 402, steel crank, heavy rods, Federal Mogul Forged Pistons, 9.9:1 compression, polished ported 781 heads 2.19/1.88 manley stainless valves, Crane Powermax Hydraulic roller 288/296 and .587,.610 lift, hardened pushrods, Crane Roller Rockers, Weiand Action Plus, 750CFM Rochester QJET, MSD HEI, MSD 8MM Wires, Dynomax Ceramic coated headers, should be about 500 H.P. 700R4 2500 stall, pretty nasty shift kit, 373 Auburn Pro Series Posi, buckets/console air/tilt/tach 4wheel discs
Daily Driver: 92 Chev Reg Cab LWB Silverado 4x4, loaded, 350 Accel filter/cap/rotor/coil/MSD wires/AC Delco RapidFire plugs, Edelbrock intake and headers, 180 degree thermostat, Hypertech Thermomaster Chip, true duals 700R4 with B@M Shift Kit for now!

[Chevyman69]

I meant 81 up style not 82.

[Chevyman69]

Oh and i forget to mention the last of the C60's/C70's with the old cab went until 91. Now those trucks with gas engines after 87 were available with TBI at least the 366's were in 87 anyway so that may be a way to get a tach for the old cab that works with a computer.

[crossy]

from chevyman69"Those engines are all governed and the tach goes to 5 grand but has no markings. I have a neighbor with an 81/82 3/4 ton 4x4 wreck that has the 82 up style guages and a tach with a redline. I have seen a few later versions 84/85 with factory tachs as well. I think I saw an 87 once "
yep they made them with redline also I have 2 here from c-60's as far as 85 ups with a tach sure i believe you saw one . somebody is buying all the ones off ebay. about 4 per week. i've sold 4 in 2 years.

[This message has been edited by crossy (edited 01-19-2002).]

[DBLSPRT68]

CROSSY and CHEVYMAN69, I have one of those c-60 clusters. It has a vac gauge and 5 grand tach (no redline) and the small gas gauge. I was thinking of putting this in my loaded 83 1/2t. Besides converting the oil press to mechanical and wiring the tach, is it a plug and play type install?? Is the factory plug of my ((dual tank)) 83 going the work the gas and other gauges, lights??? I think this is a 77 model gauge cluster. Thanks, David

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new truck: 1983 silverado c-10 2wd lwb every option 305/th350 1982 3/4 LWB CHEVY 350-TH400-2WD W/89 BURBAN FRONT. TOYOTA CELICA DAILY DRIVER. PROJECT:1965 BEL AIR 2-DOOR.
Southaven, MS

[Chevyman69]

Pull the dashes and compare but i think you will find they will work fine. As fara s the fuel guage, a lot of C60's had dual tanks with a switch and that should make no difference to your guage.

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69 CST 10, 402, steel crank, heavy rods, Federal Mogul Forged Pistons, 9.9:1 compression, polished ported 781 heads 2.19/1.88 manley stainless valves, Crane Powermax Hydraulic roller 288/296 and .587,.610 lift, hardened pushrods, Crane Roller Rockers, Weiand Action Plus, 750CFM Rochester QJET, MSD HEI, MSD 8MM Wires, Dynomax Ceramic coated headers, should be about 500 H.P. 700R4 2500 stall, pretty nasty shift kit, 373 Auburn Pro Series Posi, buckets/console air/tilt/tach 4wheel discs
Daily Driver: 92 Chev Reg Cab LWB Silverado 4x4, loaded, 350 Accel filter/cap/rotor/coil/MSD wires/AC Delco RapidFire plugs, Edelbrock intake and headers, 180 degree thermostat, Hypertech Thermomaster Chip, true duals 700R4 with B@M Shift Kit for now!

[DBLSPRT68]

Thanks for all the information. I bought this thing almost two years ago, for my 82 3/4t. Now I will be trying to put it in my 83 1/2t soon. Thanks again, David

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new truck: 1983 silverado c-10 2wd lwb every option 305/th350 1982 3/4 LWB CHEVY 350-TH400-2WD W/89 BURBAN FRONT. TOYOTA CELICA DAILY DRIVER. PROJECT:1965 BEL AIR 2-DOOR.
Southaven, MS