Tachs....how do you tell which is which? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

scoyote · 06-23-2009, 10:09 AM

I got a tach dash from a member here (can't even remember who) but now I'm wondering if it's for a 6 cylinder or a V8.

How can I tell?

I saw a photo on another thread of a tach that had 8,000 as the last number, mine only goes to 5,000 rpms.

I haven't hooked mine up yet but I'm wondering............

Anyone know how to tell the difference?

**lks dcvn** · 06-23-2009, 10:27 AM

There should be a stamp on the back of the tach (to the left of the wiring harness connector) that states 8cyl or 6cyl - that should be the easiest way.

Livrat · 06-23-2009, 10:33 AM

Both tachs are 5000 rpm's... they normally have either 8cyl or 6 cyl stamped in ink on the back.. but alot of the time that has faded away.. other than that you have to either hook it up.. (the 6 cyl tach will read about 1200rpm at a 700rpm idle hooked up to a V8) or if you know electronic circuits and you and have two tachs you can take them apart and compare the values of a resistor inside..

scoyote · 06-23-2009, 10:58 PM

Duh....I put that whole thing together a couple of times and never noticed the 8cyl stamp on it.....I'm good to go.

Thanks

06-23-2009, 10:09 AM	#1
scoyote Registered User Join Date: Oct 2008 Location: On the shores of Bull Shoals, AR Posts: 509	Tachs....how do you tell which is which? I got a tach dash from a member here (can't even remember who) but now I'm wondering if it's for a 6 cylinder or a V8. How can I tell? I saw a photo on another thread of a tach that had 8,000 as the last number, mine only goes to 5,000 rpms. I haven't hooked mine up yet but I'm wondering............ Anyone know how to tell the difference? __________________ 1972 Blazer - Bronco Orange - In the werks http://67-72chevytrucks.com/vboard/s...d.php?t=323444 1991 F250 - Hunting truck w/ Detroit rear locker, ARB front locker, front and rear winches .... and more.... 1997 Grand Cherokee - fun jeep - Detroit rear locker, ARB front locker, front winch, 411 gears, lots of lights ;-) 2004 Hot Rod DuraMax - Dnyo'd at the wheels with 525 HP and 1100 lbs torque.....mustang killer.

06-23-2009, 10:27 AM	#2
lks dcvn Registered User Join Date: Jan 2007 Location: Columbus, Ohio Posts: 4,348	Re: Tachs....how do you tell which is which? There should be a stamp on the back of the tach (to the left of the wiring harness connector) that states 8cyl or 6cyl - that should be the easiest way.

06-23-2009, 10:33 AM	#3
Livrat Member #1049 Join Date: Jun 2000 Location: Troy Montana Posts: 3,940	Re: Tachs....how do you tell which is which? Both tachs are 5000 rpm's... they normally have either 8cyl or 6 cyl stamped in ink on the back.. but alot of the time that has faded away.. other than that you have to either hook it up.. (the 6 cyl tach will read about 1200rpm at a 700rpm idle hooked up to a V8) or if you know electronic circuits and you and have two tachs you can take them apart and compare the values of a resistor inside..

06-23-2009, 10:58 PM	#4
scoyote Registered User Join Date: Oct 2008 Location: On the shores of Bull Shoals, AR Posts: 509	Re: Tachs....how do you tell which is which? Duh....I put that whole thing together a couple of times and never noticed the 8cyl stamp on it.....I'm good to go. Thanks __________________ 1972 Blazer - Bronco Orange - In the werks http://67-72chevytrucks.com/vboard/s...d.php?t=323444 1991 F250 - Hunting truck w/ Detroit rear locker, ARB front locker, front and rear winches .... and more.... 1997 Grand Cherokee - fun jeep - Detroit rear locker, ARB front locker, front winch, 411 gears, lots of lights ;-) 2004 Hot Rod DuraMax - Dnyo'd at the wheels with 525 HP and 1100 lbs torque.....mustang killer.

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