Avette4me

Finally got rid of that unsightly, stupid, and just plain wrong, 85 MPH speedometer and replaced it with a 140 MPH version from Redline. After reading my shop manual and many recent posts concerning the change over, I thought it would be a project for the entire weekend.

With some very good advise from John (@ Redline), I was pleasantly surprised. I did the complete change over on 25 minutes. I think that now that I have done one, I could likely do it in 15, and I’m certainly not some kind of genius (if it weren’t for spell check, I may not even spell it correctly).

Following is the method I used. I would strongly recommend that anyone changing theirs out, wait until you get the replacement before starting. Waiting will help you better understand the speedometer cable keeper operation.

1. Remove 5 screws that attach clear portion
2. Remove 6 allen head screws (3 at speedo and 3 at tack)
a. This will allow the removal of the small cover plate rather than the entire “bezel” so you don’t have to mess with the lights and tack connections.
3. Remove the 3 hex head screws that hold the speedo in place.
4. Remove the A/C duct
5. Reach behind and while holding the speedo cable, push the spring keeper towards the speedometer (the push point is located on the bottom side of the speedo/cable connection point).
a. While pushing forward on the keeper, pull out on the speedometer
b. This is the really difficult part, mainly because of reaching behind the dash while pulling on the speedo (I strongly recommend a contortion class :boxing )
c. Once you are doing all three at once (holding cable, pushing on keeper, and pulling on speedo) the assembly will come apart easily!
6. When reassembling, the reverse. The speedo cable can simply be pushed back into place.

Hope this helps someone in the future. :smash:

81VETTOM

I got one to put in my 81, just haven't got to it yet. I want a felloow vetter to make the odometers match.
thanks can't wait to do mine. :smash:

Dalannex

Where do you guys get these speedo's (Redline???????) and do they have a matching tach??????? And what do they cost$$$$$$$$$ I need to put a new board in my tach, so that 's $100, and I want a bigger speedo, so there is a possibility of doing both at the same time. I see Mid America has a NOS 140 or 160 or something speedo for the later C3's but they're like $200. (I don't remember the details for sure right now)


-Justin

Avette4me

Call John at Redline - 800/375-2310. I paid $56.50 w/exchange. He will allow you 30 days to ship the old speedo back, or pay an additional $300.00

MN-Brent

Lonnie
Thanks for the info. Ive had this Redline speedo redo on my list of things to do for some time since mine went on strike.

I need to prove that the speedo cable is turning first though before I yank the speedo.

Brent...

Dalannex

Thanks. Does this new speedo work with the stock speedo cable and speedo drive gear in the tranny tailshaft? Or do I need to remove the tailshaft housing to change the drive gear in the transmission so that it reads correctly?????

-Justin

Avette4me

Hey Justin,

The new speedometer works perfectly with your existing cable etc. It's calibrated to GM specs, so as long as your old one was accurate, the new one will be as well.

I will be checking mine as soon as the snow is gone from here since bigger tires, etc will effect the speedo's accuracy. It's my understanding that 1 tooth in the tranny gear will change the speedo about 5 to 7 MPH and it's relatively easy to change.

Good Luck to ya
Lonny

corvettemaster

This is also on my 2 do list. I have one question tho. Is the cross flags on the 140 mph speedo from Redline, the 80-82 look, or the 78 look?

Avette4me

They're the 78 or 79 look. However, once you get the speedo in, it's pretty hard to tell the difference. Other than Vette enthusiasts, most people would likely be unable to tell the difference. I would bet they would be quicker to comment on the 85 MPH speedo.

My thinking was, while I would prefer the correct flags, I changed the car from original anyway and since the look is very close, I prefer 140 over 85 any day.

82dukman

Actually the only thing that is significantly different is the KM/H. They are "blue" instead of orange

Double Aught

Congrats on a job well done! :thumbs: That would be one of the first things I would do if I had the 80-82 model. :yesnod:

mark79,80

To make it much easier to remove the speedometer cable from the back
of the speedometer, first remove the speedometer cable at the cruise
control transducer. If you don't have cruise control, then remove the
speedometer cable from the transmission.
This will enable sliding the speedometer cable out as you pull on the
speedometer. Once the speedometer is pulled out a couble of inches
from the instrument bezel, you can reach your hand behind the speedometer
and easily push in on the clip that holds the speedometer cable. Using
this method, there is no need to remove the AC duct and reach your hand
up from under the dash.

Dalannex

Great tip. See what you guys have gone and done now? You've made me HAVE to spend more money and get a new speedo. Way to go. :lol:

CORVETTE CRAIG

Just my 2 cents:
For any of you wondering or still contemplating the purshase of these Redline Speedo's, DON'T.
Dollar for Dollar, this has (and still is) the best overall upgrade I ever put in my Vette.
P.S. Becareful on your first test drive. You'll spend more time looking at the speedo, than the road.

av8vito

Gotta agree, the Redline 140 MPH upgrade was well worth the money. As I remember, if you already have a core, the upgrade was only $57.00. I ended up removing the entire speedo/tach housing while I upgraded the speedo in order to replace all the light bulbs and replace the tach circuit board. The tach indicated accurate RPM at start up, but as the car heated up, the indicated RPM would gradually creep up until it was reading about 500 RPM higher than it should for a given speed. Strange. New circuit board fixed this.

Armstrong

I want to do this in the VERY near future but at the moment am trying to figure out why my speedo reads about 10 MPH too fast. My needle does jump and I'm planning on replacing the cable when I do the speedo but does anybody have any ideas as too why it reads too fast???

Avette4me

Have you changed the tires from the original size. I believe it's the most common cause. It will also change with rear end changes, etc.

kgraumann

You may have to have the speedo calibrated. John at Redline does it free on all the speedos he sells, and will walk you through what you have to do. Best thing to do is call him.

I had to recalibrate mine also, and John did it for free.