Tach differences 6cyl vrs 8cyl - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gaddman · 07-06-2004, 11:56 PM

I have an original dash assembly with a 6 cyl tach and air pressure gauge. It was in a heavy duty pickup, probably a 70 or newer. It appears to be original to the truck, but I do not know for sure. Does that sound right? What would the air pressure gauge be doing in a regular pickup? I don't think it had air brakes or anything. I thought the air pressure was a big C30, dump truck kinda thing?

Anyway, I've not seen but a couple of these 6 cyl tachs. Are they fairly rare? Can they be converted to work with an 8 cyl? If not, anyone got a 8 cyl version they wanna trade?

Thanks!

JimKshortstep4x4 · 07-07-2004, 06:47 AM

The air pressure gauge probably was in a larger truck originally as a pickup would have no need unless someone installed a compressor on it.

You can adjust a 6 cylinder tach to work on an 8 cylinder. There is a small screw on the back of the tach with a piece of tape covering it up. Just adjust it using another tach for reference, (both hooked up to the same engine).

Jim

07-06-2004, 11:56 PM	#1
gaddman Registered User Join Date: Apr 2001 Location: Scottsburg, In Posts: 160	Tach differences 6cyl vrs 8cyl I have an original dash assembly with a 6 cyl tach and air pressure gauge. It was in a heavy duty pickup, probably a 70 or newer. It appears to be original to the truck, but I do not know for sure. Does that sound right? What would the air pressure gauge be doing in a regular pickup? I don't think it had air brakes or anything. I thought the air pressure was a big C30, dump truck kinda thing? Anyway, I've not seen but a couple of these 6 cyl tachs. Are they fairly rare? Can they be converted to work with an 8 cyl? If not, anyone got a 8 cyl version they wanna trade? Thanks! __________________ Gaddman Scottsburg, In 67 SWB w/93 step bed 68 LWB Fleetside C10 Custom 50 Chevy 3600 74 Norton Commando 850 72 Norton Commando 750

07-07-2004, 06:47 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	The air pressure gauge probably was in a larger truck originally as a pickup would have no need unless someone installed a compressor on it. You can adjust a 6 cylinder tach to work on an 8 cylinder. There is a small screw on the back of the tach with a piece of tape covering it up. Just adjust it using another tach for reference, (both hooked up to the same engine). Jim



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