Author Topic: Tach cluster swap  (Read 4598 times)

Offline robtco99

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Tach cluster swap
« on: March 06, 2008, 07:28:16 pm »
I have regular gauges in my 79 k20 & i bought a whole factory tach cluster today at the junkyard from a 78 c10. What do i need to do to make the tach cluster work in my truck with non tach gauges? Thanks
1979 K20 4X4 Camper Special

Offline VileZambonie

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Re: Tach cluster swap
« Reply #1 on: March 06, 2008, 07:40:26 pm »
You need a schematic and a tach signal wire off of the negative side of your coil.
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Prong

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Re: Tach cluster swap
« Reply #2 on: March 10, 2008, 02:42:36 am »
As long as that cluster came from a 78-80, it'll be a a plug and chug operation. All you need is a ground wire from tach to body (I used an unused slot on the existing ground junction behind the upper left corner of dash), a 12v Ignition hot source (found a unused spot on the fusebox), and a lead to the tach terminal on the distributor. Your harness will plug right into the new cluster and you're good to go. It took me longer to make up the tach wiring and make it look nice than it did to do the rest of the operation.
79 K10 SB 4x4 383/Th350
79 K10 LB 4x4 350/SM465