? Will a factory 74 tach fit into a 86 dash

[68customcamper]

I have a 86 gmc k1500 and i am looking to install a factory tach out of a 74 i know the guages are removable does anyone have any feedback on if this is possible.

Thanks, Mike.

[Russell]

The cluster will physically fit in, but there are some important differences.

The 74 cluster will have an amp gauge, and a mechanical oil pressure gauge. Your truck will have a volt meter, and an electric oil pressure gauge. If you want to bolt the older tach cluster in, you'll have to convert to the mechanical oil gauge (which I would highly reccomend, as they are far more accurate) and you'll have to either re-wire wire your truck for the amp gauge, or swap your old volt meter in instead.

Make sure that the circuit sheet on the cluster runs to a positive and negative wire on the proper posts of the volt gauge before you plug it in. If you want to convert and use the amp gauge, you have to run the amp gauge inline of a major power wire to measure the amount of current passing through it while the truck is on.

Converting to a mechanical oil pressure gauge is easy, just get the steel line from the older truck, route it through your firewall, un-thread your old sending unit, and thread the steel line's adapter + the steel line itself straight in. The wire for the old gauge can just be left hanging behind the intake.

You will also have to swap your newer temp gauge in, as the newer and older trucks have different sending units, and unfortunately are not interchangeable due to different sized holes in the heads. You will not have to change any wiring, just swap the gauge.

Might be easiest to buy a newer 78+ tach cluster (if you haven't already bought the 74 cluster), as it will bolt straight in, and everything will be compatable with your stock sending units etc.

[68customcamper]

cool thanks thats what i needed to know.

[Prong]

This link may help.
http://73-87.com/7387garage/interior...achometers.htm

[Captkaos]

You would have to completely rewire the 80's truck for it to work due to the amp vs volt or you will fry the wiring. You would also need a printed curcuit for the Volts if you planned to go the convert to Volt gauge route. I won't be a simple pull out the old and put in the new. Plus you need the 76-77 or 78-80 volt guage as the fonts changed in 1981 and won't match pre-81.

[68customcamper]

thanks guys that helps alot