Hey, Good Evening Out there in Vette Land. Got a question re: my speedometer. It is the 85 mph speedometer. I believe it is the wrong one, been changed by previous owner. Does anyone know if that is the correct one. All I have seen on 79's is the 140 mph speedo. Thanks in advance for any info you can shoot my way. All the best, Jimmy

 

I'm thinking that 85MPH speedo started in 81. Horrible thing.
call around to Corvette salvage yards and find a good used replacement.

 

Due to an extended production run in 79, the supply of 140mph speedometers was depleted sometime after 44598, and GM continued with the 85mph speedo. Do you have a late production ?

 

After 1979 the only car that had a speedometer that went over 85mph was the deloran... That way you could accurately tell you were going 88mph....

 

I believe 85 MPH speedos were used on L48 engines but I could be wrong.

 

Doc Brown had to rig up a digital speedometer to read 88 mph, which likely made it easier for the audience to see what was going on than watching a needle anyway.

I found a 140 mph speedo cluster on this Forum.

 

This is the correct answer.

1980 Corvettes were scheduled to get the 85 MPH speedometer, but parts shortages force them to put it in about the last 9000 79's, basically those 79's built in August and September 79. It's also possible if the OP's car is late enough it could have the two door rear storage compartment normally found in 80-82's. The three door style rear storage compartment typically found in all 68-79 Corvettes was replaced by the 80-82 style two door compartment on about the last 500-600 79's.

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L-48's and L-82's all used the same speedometers, 140 MPH till about August 79, when it was replaced with the 85 MPH one. L-82's did use a different tach with a higher redline and "L-82" printed on the tach's face.

 

My 1979 was built 8/3/79. The last 6 digits are 446378. It has the 140 speedo in it. It also has 3 door storage compartments. My engine is a L-82. The tach has L-82 on the face and it relines at 6k.

 

Correct me If I'm wrong but the speedo/tach would have come to St Louis as an assembly, labeled L48 or L82, I'm talking the 140 MPH speedo. So the range of 44598 to 48940 suggests vehilces could have shipped with either the 140 or 85 mph speedo. As bagger shows with his VIN of 46378, narrows the range but there could have been VINs shipped with the 140 mph earlier than bagger but after the 44598.

 

If you go to the C3 registry and look at some of the pics, it shows vin 48355 with a 140 speedo (8/17 build) & vin 48855 with a 85mph speedo . So sometime in this production period.

 

Perhaps a dumb question, but how far ahead of production were the tach/speedo assemblies sent to St Louis and in what quantities? Would they have ran out of 140MPH for both the L48 & L82 at the same time? Or have more of one than the other on hand.

 

GM rarely had a hard cut off date for when any Running Model Change (RMC) took place. As old parts got used up new ones were fazed into production. GM didn't waist anything, they usually used up their supply of old parts first. The redesigned parts and old parts sometimes appeared to run concurrently, as the new parts got mixed into the inventory supply. In the 60's and 70's companies didn't have the inventory control systems that we have today.

The 79 speedometer/tachometer clusters did come to the assembly line already pre-assembled. Because of this it's possible that maybe L-48's got 85 MPH speedometers sooner then L-82's, but it's just as likely the opposite happened, maybe more so? Since they sold fewer L-82's they may have had fewer assembled L-82 speedo/tach clusters on hand and used then up quicker? Either way I don't think there would likely be more then a couple days difference since production lead times were long enough that Chevrolet usually had a pretty good idea of how many orders they had for L-82's verse L-48's.

I don't have an NCRS 78-79 Judging Manual near by, but going from memory I think the NCRS found through their surveys they did years ago that the 85 MPH speedometers started showing up somewhere between VIN 44500 and 48500. As time passes, and if people care to do more research, I'm sure a tighter cut off point for the change may someday be learned.

Something else to look for on 79's with the 85 MPH speedometer is the "Choke" light in the bottom of the tach. 80 tach's had a choke warning light in the bottom of the tach. Apparently some of the 79's that got the 85 MPH speedometers also got tach's with the Choke light lens, but it was non functioning on 79's, and had no bulb behind the lens.

 

The 78/79 judging manual claims anytime after 44598 which technically is correct but with new & recent information it can be narrowed down. . Guess is mid August.

OP you started this thread. What is your vin number ?

 

You likely have a newer edition of the 78-79 Manual than I have. Mine's a First Edition that Lewis Russell sent me to review when I was part of his team working on the 80-82 Judging Manual. I know the First Edition gives a VIN range when the switch over took place based on the last VIN with a 140 speedometer and the first with the 85 MPH one, found in the surveys Lewis had. For reference, the First Edition shows "after s/n 44598 and before s/n 48940".

I belonged to a Corvette Club in the 70's that use to do a big two day indoor Corvette show every year in the the South Jersey/Philadelphia area. In 79 it was held in August at an armory in Philadelphia and was sponsored by a local Chevrolet dealer, Matt Slapp. The dealer displayed a 79 at our show and someone in our club noticed it had the 85 MPH speedometer, which was a surprise to all of us. I did a lot of photography for the club and shot the show. I know I took pictures of the 79 because I didn't think anyone years later would believe some 79's came with the 85 MPH speedometer, but that was 25 years and thousands of slides ago, so I don't know if I could ever find them today. If I remember right it was a dark green 79 with light doeskin interior, and I know it had the two door rear storage compartments too.

 

We've assembled a revision team for the 78-79 team and this edition would be the 4th. The 79 guys are exploring the 85 speedo introduction range so this is a great discussion that may narrow that range.

The NCRS 78-79 revision team is looking to add 79 members who wish to contribute to the revision. I know I couldn't find slides/photos from 75 years ago. And when found, their resolution isn't sufficient for colored print but they provide data that helps with understanding the ROLLING PRODUCTION CHANGES in the late 70s. These two years, 50,000 units were assembled per year compared to 30,000 in the early 30s...part differences within the year are mind boggling!

 

Thanks Sir, Will do. All the best, Jimmy

 

Hey Thanks. I don't know if mine is a late model but I'll check. It is a load off my mind though that it is probably the original speedo. Thanks for that. Now I suppose my mileage is correct too. Many thanks Jimmy

 

Dearest Vette Brothers and Sisters, Thanks so much for the many replies. It is a load off my mind that I most likely have the correct speedo "and mileage" on the odometer. That was what I was concerned about, I figured the dealer may have dumped in a different speedo with lower mileage. Many Thanks to All, And All the Best, Jimmy

 

I will as advised check my VIN #. Just trying to find my title to take a look. BTW, You guys are great and very knowledgeable. I am amazed