Where did you mount your tach in a 73-87 ? - Page 3 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

badone07 · 05-25-2005, 09:57 AM

Nothing fancy. Tach mounted on the column. Idiot lights still connected and functioning. 3 mechanical gauge pack mounted where change, junk, etc. pocket used to be for a non-a/c cab. Maybe one day I'll get around to putting the dashpad back on.

NeCrOmAnCeR · 05-26-2005, 11:48 AM

Here is mine, yes it is accurate. I have recalabrated a few for other board members as well. If I thought about it, I'd only have made it go to 7K, but it looks good.

**N2TRUX** · 05-26-2005, 08:58 PM

Quote:

Originally Posted by NeCrOmAnCeR

Here is mine, yes it is accurate. I have recalabrated a few for other board members as well. If I thought about it, I'd only have made it go to 7K, but it looks good.

OK, I give up, how did you get an 8k tach....

gldevall · 05-26-2005, 10:07 PM

Quote:

Originally Posted by theintimidator3

I drilled 2 small holes beside the sun visor and mounted it up there. I then ran my wires and hid them in the weatherstripping running down and through the fusebox etc.. It looks good, as long as you don't use your sun visor.

Got any pics? I'm having a hard time picturing that.

ElGracho · 05-26-2005, 10:12 PM

Quote:

Originally Posted by NeCrOmAnCeR

Here is mine, yes it is accurate. I have recalabrated a few for other board members as well. If I thought about it, I'd only have made it go to 7K, but it looks good.

That is badass.

gldevall · 05-26-2005, 10:20 PM

Here's mine.

MylilBowTie · 05-27-2005, 12:41 AM

Camaro Tach? Im guessing?

*rage'nrat638* · 05-27-2005, 04:07 PM

inthe dash on the dash

NeCrOmAnCeR · 05-27-2005, 05:19 PM

No, original GM truck tach, I recalabrated it to read 8K at full scale, and then I made a magnetic face to go over the original so I can convert it back if I want.

ElGracho · 05-27-2005, 07:06 PM

Quote:

Originally Posted by NeCrOmAnCeR

No, original GM truck tach, I recalabrated it to read 8K at full scale, and then I made a magnetic face to go over the original so I can convert it back if I want.

Do you have a schematic of the tach circuit? or any other theory of operation? What did you change to calibrate it?

bigblock73 · 05-28-2005, 03:42 AM

Here is the one I had in my Blazer, and the article I wrote for the one I put in Yeller.

http://www.73-87.com/7387garage/inte...ge_surface.htm

FYI - you can mount a tach on the column and NOT have it move when you change gears...you just have to be careful with where you put the mounting strap.

u2slow · 05-28-2005, 09:55 AM

Quote:

Originally Posted by bigblock73

FYI - you can mount a tach on the column and NOT have it move when you change gears...you just have to be careful with where you put the mounting strap.

The whole 'moving tach' problem just dawned on me now.

Time for a manual trans or a floor shifter

benscool1 · 05-28-2005, 01:16 PM

Does anybody have pics of the sunvisor mounted tach?

NeCrOmAnCeR · 05-28-2005, 11:31 PM

I have posted on another thread awhile back, I tried to find it but with search disabled I gave up after a few hundred pages.
Basically I use a function generator to generate the appropriate frequency to simulate the upper RPM limit I am modifying the tach to read, and eliminate the factory 'trim' resistor. I substitute a variable resistor in its place and adjust it to give the correct readings. (I do this over the entire RPM range to best match the tachs linearity with the new face) I then replace the variable resistor with a high tolerance resistor of the same measurement. Of course I check all the circuit components to make sure the capacitors are still reading the correct value and replace those as needed.

Magic0nas · 03-22-2012, 02:54 AM

Guys i have a question im looking for tach (NOS or OEM ) to fit into my truck for 1979 Silverado 454 i found one on ebay looks like the one in the photo. My question is how to fit it into the truck? is there anything i have to buy or change in order to work>?
My truck is fully loaded.

Thanx
Nas

motornut · 03-22-2012, 09:25 PM

may want to have a look below in the 78 i went from idiots to factory tach/gauges

tobytuttle · 03-22-2012, 09:35 PM

Quote:

Originally Posted by bigarmzz

man, thats a sweet set up there.......whats that off of??

thats the c50-c70 style note the 5 grand tach..they made them less like 4 grand too i think...matters what motor was in it

05-25-2005, 09:57 AM	#51
badone07 Project 2 Resume Join Date: May 2004 Location: Jim Thorpe, PA Posts: 884	Nothing fancy. Tach mounted on the column. Idiot lights still connected and functioning. 3 mechanical gauge pack mounted where change, junk, etc. pocket used to be for a non-a/c cab. Maybe one day I'll get around to putting the dashpad back on. Attached Images __________________ John 1984 C30 Chevy Crew Cab Dually 1998 Jeep Cherokee 4x4 2004 Chevy Trailblazer 4x4 (wife's) 1970 Mustang FB fully tubed (getting 521 BBF & powerglide) 1978 Nova 2dr (going BBCaddy & S.P. th400) 1984 Monte SS (circle track car)

05-26-2005, 11:48 AM	#52
NeCrOmAnCeR Registered User Join Date: Feb 2004 Location: Hodgenville, Ky Posts: 735	Here is mine, yes it is accurate. I have recalabrated a few for other board members as well. If I thought about it, I'd only have made it go to 7K, but it looks good. Attached Images

05-26-2005, 10:20 PM	#56
gldevall Registered User Join Date: Mar 2003 Location: Walker, LA Posts: 2,925	Here's mine. Attached Images __________________ Gary -1986 SWB: lowered 4/6, SOLD!!! -Best 1/4 mile: 14.51 @ 91.01 MPH -2001 Pewter Tahoe, billet grill, Corsa Sport Cat-back, K&N FIPK SOLD!!! -2004 Z-71 Extended cab with a flowmaster, BDS 6.5", 3" BL, 35x12.5x18 Trail Grapplers on Pro-Comp 18x9 wheels

05-27-2005, 12:41 AM	#57
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Camaro Tach? Im guessing? __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

05-27-2005, 04:07 PM	#58
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	inthe dash on the dash Last edited by rage'nrat638; 07-12-2007 at 07:04 AM.

05-27-2005, 05:19 PM	#59
NeCrOmAnCeR Registered User Join Date: Feb 2004 Location: Hodgenville, Ky Posts: 735	No, original GM truck tach, I recalabrated it to read 8K at full scale, and then I made a magnetic face to go over the original so I can convert it back if I want.

05-28-2005, 03:42 AM	#61
bigblock73 yeller Join Date: Oct 2001 Location: Twin Cities Posts: 13,826	Here is the one I had in my Blazer, and the article I wrote for the one I put in Yeller. http://www.73-87.com/7387garage/inte...ge_surface.htm FYI - you can mount a tach on the column and NOT have it move when you change gears...you just have to be careful with where you put the mounting strap. Attached Images __________________ Jeff 73-87.com 73-87.com Facebook page 73-87 cab corner 6x9 speaker brackets for sale 67-72 cab corner speaker brackets for sale 47-54 cab corner speaker brackets for sale

05-28-2005, 01:16 PM	#63
benscool1 Registered User Join Date: Mar 2003 Location: Williamsfield, IL Posts: 781	Does anybody have pics of the sunvisor mounted tach? __________________ Ben 84 C10 Silverado 14 Silverado Z71

05-28-2005, 11:31 PM	#64
NeCrOmAnCeR Registered User Join Date: Feb 2004 Location: Hodgenville, Ky Posts: 735	I have posted on another thread awhile back, I tried to find it but with search disabled I gave up after a few hundred pages. Basically I use a function generator to generate the appropriate frequency to simulate the upper RPM limit I am modifying the tach to read, and eliminate the factory 'trim' resistor. I substitute a variable resistor in its place and adjust it to give the correct readings. (I do this over the entire RPM range to best match the tachs linearity with the new face) I then replace the variable resistor with a high tolerance resistor of the same measurement. Of course I check all the circuit components to make sure the capacitors are still reading the correct value and replace those as needed.

03-22-2012, 02:54 AM	#65
Magic0nas Registered User Join Date: Oct 2011 Location: Lafayette Posts: 50	Re: Where did you mount your tach in a 73-87 ? Guys i have a question im looking for tach (NOS or OEM ) to fit into my truck for 1979 Silverado 454 i found one on ebay looks like the one in the photo. My question is how to fit it into the truck? is there anything i have to buy or change in order to work>? My truck is fully loaded. Thanx Nas

03-22-2012, 09:25 PM	#66
motornut 78K & 79C Jimmys Join Date: Nov 2009 Location: Ottawa Ont CANADA Posts: 7,901	Re: Where did you mount your tach in a 73-87 ? may want to have a look below in the 78 i went from idiots to factory tach/gauges Attached Images __________________ John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350



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