Wrong Tach?
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,539
Likes: 63
From: new ulm mn
Wrong Tach?
Have a '69 L68 that has a tach with a 6500 redline which is the wrong tach. The correct tach should have a 5600 redline. Always thought someone had changed it at sometime in the past. Bought the right tach and am in the process of changing it. After pulling the instrument panel I see that both the tach and the speedo have inspection dates within 2 days of each other and the dates match the build date of the car. Would GM put the wrong tach in the car? Would that be dangerous as you could over rev the L68? Anyone know?
Team Owner
Joined: Sep 2006
Posts: 31,110
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From: Westminster Maryland
Hi l,
The chance of the wrong tach being installed in the car in St.Louis is 'extremely' low, but not absolutely 'impossible'.
Are you saying the dates on the tach/speedometer are the SAME as the trim tag date?
Regards,
Alan
The chance of the wrong tach being installed in the car in St.Louis is 'extremely' low, but not absolutely 'impossible'.
Are you saying the dates on the tach/speedometer are the SAME as the trim tag date?
Regards,
Alan
Race Director
Joined: Oct 2000
Posts: 12,596
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From: Shamong, NJ
There have been times where Chevrolet substituted tachs with different redlines, when there was a shortage of parts, but I've never heard of any documented cases involving Corvettes. I can't imagine that they would intentionally install a tach with a higher redline though. A higher redline could easily lead to warranty claims, something GM usually tries to avoid.
In 67, the Z/28 and 396/375 Camaros came with a 6000 redline, 7000 RPM tach. Around May 67, GM ran into a shortage of 6000 redline tachs. As a result, Z/28's and 396/375's built from May through July, ended up with tachs with 5000 and 5500 RPM redlines. Here they substituted a lower redline tach, but then GM never had a tach with a redline higher than 6000 for Camaros.
At one time, I worked as a fleet manager for a company, and I saw a lot of strange things. I had a Cavalier come in with a chrome mirror on one door and a painted sport mirror on the other, and a Celebrity with 3 Chevy rally wheels and a Cutlass Ciera rally. So I won't say that it wasn't a mistake by St. Louis, but it would be hard to prove.
In 67, the Z/28 and 396/375 Camaros came with a 6000 redline, 7000 RPM tach. Around May 67, GM ran into a shortage of 6000 redline tachs. As a result, Z/28's and 396/375's built from May through July, ended up with tachs with 5000 and 5500 RPM redlines. Here they substituted a lower redline tach, but then GM never had a tach with a redline higher than 6000 for Camaros.
At one time, I worked as a fleet manager for a company, and I saw a lot of strange things. I had a Cavalier come in with a chrome mirror on one door and a painted sport mirror on the other, and a Celebrity with 3 Chevy rally wheels and a Cutlass Ciera rally. So I won't say that it wasn't a mistake by St. Louis, but it would be hard to prove.
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,539
Likes: 63
From: new ulm mn
I understand that, but if your new corvette has a tach with a 6500 redline, that is what you will drive it to. Remember, the car was new then and there was no network of corvette historians to call it wrong.
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,539
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From: new ulm mn
The trim tag has a build date of July 3rd which is consistent with all the dates on the drive train. The speedo and tach have April 14th and 19th stamped on them respectively. These items are not easily changed so I can't see anyone changing them for the heck of it.
Le Mans Master
Joined: Oct 2006
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
I just replaced the aftermarket gauges (Speedo/tach) with factory style stuff I had acquired. The speedo I got had problems with the odometer gears so I got a rebulti for that, and the tach had a 5k redline which was not correct for a solid lifter BB. New tach face was $35 and 30 minutes to change the face. Done.
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Team Owner
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From: Crossville TN
The final assembly line would always put the wrong tach in the car IF the correct one was out of stock at the line. They would NEVER shut the line down because the correct tach was not available.
Last edited by 7T1vette; Mar 29, 2017 at 05:59 PM.
Is my vette stock?? HAHA
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Hell ya its possible. A little dyslexic episode from not paying attention could easily be to blame.6500 5600 close enough. Those guys were on an assembly line. Hell i worked at SIG inspecting pistols and rifles. You wanna see some crap. Sights in backwards, no sights, safteys in backwards, wrong mags, you name it, someone loooking for the next break could care less. The managers want numbers, good or bad, who cares, just give us the big numbers baby!!!!
If you want correct just buy the face and swap it and put the other in the closet for future pricing. Just dont touch the fluorescent numbers. Old fluorescent will rub off on contact.
If you want correct just buy the face and swap it and put the other in the closet for future pricing. Just dont touch the fluorescent numbers. Old fluorescent will rub off on contact.
Last edited by Rescue Rogers; Mar 29, 2017 at 08:37 PM.
Burning Brakes
Joined: Oct 2003
Posts: 836
Likes: 26
From: Harrisburg Pa
I just looked in my Vette Vues fact book and it says that a L68 should have a 6000 red line.
I also checked 4 different parts places and the tachs they list also say different red lines for your engine and HP., so it looks like no one has a real answer here.
Im just saying to check your facts before you change something that may be correct, maybe you have a L88,
Do you have the Tank Sticker?
I also checked 4 different parts places and the tachs they list also say different red lines for your engine and HP., so it looks like no one has a real answer here.
Im just saying to check your facts before you change something that may be correct, maybe you have a L88,
Do you have the Tank Sticker?
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Who knows what they did in those days or what some guy did when it was 2 yrs old
Put a temp tach in that is of good quality compare cruise rpms go from there
honesstly cable tachs are cool but if looing for accuracy a joke!! many 7k Lt1s that arent scratching 6k. Big deal?up to you!
MY new Sun tach is fine any time unless on the throttle hard it doesnt keep up under WOT up top lags by almost 1000 rpm!!
Hope this helps
Put a temp tach in that is of good quality compare cruise rpms go from there
honesstly cable tachs are cool but if looing for accuracy a joke!! many 7k Lt1s that arent scratching 6k. Big deal?up to you!
MY new Sun tach is fine any time unless on the throttle hard it doesnt keep up under WOT up top lags by almost 1000 rpm!!
Hope this helps
Last edited by cv67; Mar 30, 2017 at 02:21 AM.
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,539
Likes: 63
From: new ulm mn
Thanks for all the input. Was just curious and probably will never know why it's the wrong tach. After taking everything apart, it looks to be all original and not replaced so who knows. Got the new tach already installed. thanks again.