Will stock GM HEI work on an original Tachometer? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

CSTGURU · 05-15-2022, 11:17 PM

Has anyone had any experience hooking up a factory 67-72 tach dash to a totally stock GM HEI from the late 1970's/early 80's. thanks for the input.

body bolt · 05-15-2022, 11:44 PM

It does.

**Smitty** · 05-16-2022, 12:11 AM

Works great on mine!

**Palf70Step** · 05-16-2022, 07:40 AM

The one on mine is not accurate. Have tried all the tricks mentioned to make them compatible, but the RPMs change and get off by over 1000 RPMs the higher you go in the RPM range. Works perfect on a non-HEI distributor, just not on the HEI.

72c20customcamper · 05-16-2022, 10:22 AM

Not on my truck but the OEM knee knocker tach works with the HEI on my Chevelle .

**HO455** · 05-16-2022, 10:53 PM

Quote:

Originally Posted by Palf70Step

The one on mine is not accurate. Have tried all the tricks mentioned to make them compatible, but the RPMs change and get off by over 1000 RPMs the higher you go in the RPM range. Works perfect on a non-HEI distributor, just not on the HEI.

I had similar experiences on my Burban.

**StingRay** · 05-16-2022, 03:15 PM

Works good on my stuff.

**Accelo** · 05-17-2022, 12:58 AM

https://ck5.com/forums/threads/info-...signal.293103/

**'68OrangeSunshine** · 05-17-2022, 03:27 AM

Going the other way, my SunTach by AutoMeter works well. It's on a 292 L6 on a '68 C/10 Stepside shortbed in original 516 Orange.
Tach and coil work OK with stock Delco Remy HEI* parts. No interference. No signal-induced misfires. Play well together.
Same tach worked well with points, too.

leftybass209 · 05-18-2022, 05:32 PM

As others mentioned... Mine reads slightly low at idle, and gets significantly farther off as RPM's increase.

There is someone making boards for these for half the price of a new one, but i've yet to pull out the tach and test the circuit components on the board to see if they're good.

I'm hoping i get good news and find a resistor out of spec that can be changed for a couple bucks... but whose that lucky!?

05-15-2022, 11:17 PM	#1
CSTGURU Registered User Join Date: May 2015 Location: MANITOBA Posts: 48	Will stock GM HEI work on an original Tachometer? Has anyone had any experience hooking up a factory 67-72 tach dash to a totally stock GM HEI from the late 1970's/early 80's. thanks for the input.

05-15-2022, 11:44 PM	#2
body bolt Registered User Join Date: Oct 2020 Location: Albuquerque, New Mexico Posts: 474	Re: Will stock GM HEI work on an original Tachometer? It does.

05-16-2022, 12:11 AM	#3
Smitty Senior Member Join Date: Dec 1999 Location: Spring Valley, Ca. Posts: 1,136	Re: Will stock GM HEI work on an original Tachometer? Works great on mine! __________________ Smitty '71 Short Fleetside Spring Valley, Ca.

05-16-2022, 07:40 AM	#4
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,216	Re: Will stock GM HEI work on an original Tachometer? The one on mine is not accurate. Have tried all the tricks mentioned to make them compatible, but the RPMs change and get off by over 1000 RPMs the higher you go in the RPM range. Works perfect on a non-HEI distributor, just not on the HEI. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

05-16-2022, 10:22 AM	#5
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,716	Re: Will stock GM HEI work on an original Tachometer? Not on my truck but the OEM knee knocker tach works with the HEI on my Chevelle . __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

05-16-2022, 03:15 PM	#7
StingRay Senior Member Join Date: Mar 2000 Location: Saskatoon,SK,Canada Posts: 2,476	Re: Will stock GM HEI work on an original Tachometer? Works good on my stuff. __________________ Saskatoon, Saskatchewan Canada

05-17-2022, 12:58 AM	#8
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,295	Re: Will stock GM HEI work on an original Tachometer? https://ck5.com/forums/threads/info-...signal.293103/

05-17-2022, 03:27 AM	#9
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,504	Re: Will stock GM HEI work on an original Tachometer? Going the other way, my SunTach by AutoMeter works well. It's on a 292 L6 on a '68 C/10 Stepside shortbed in original 516 Orange. Tach and coil work OK with stock Delco Remy HEI* parts. No interference. No signal-induced misfires. Play well together. Same tach worked well with points, too. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 05-18-2022 at 05:57 PM.

05-18-2022, 05:32 PM	#10
leftybass209 Registered User Join Date: Feb 2011 Location: Modesto, CA Posts: 2,189	Re: Will stock GM HEI work on an original Tachometer? As others mentioned... Mine reads slightly low at idle, and gets significantly farther off as RPM's increase. There is someone making boards for these for half the price of a new one, but i've yet to pull out the tach and test the circuit components on the board to see if they're good. I'm hoping i get good news and find a resistor out of spec that can be changed for a couple bucks... but whose that lucky!?



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