how do i find out if my 1977 corvette is an early or late modle using the vin#

 

According to the Corvette Black Book, the '77 VIN ranged from 1Z37L7S400001 through 1Z37L7S449213. The fifth digit varies as follows: L=350ci, 180hp, X=350ci, 210hp.

You can place your car in the sequence by comparing the last 5 digits with the above range.

Cheers,
Pete

 

Don’t know by VIN numbers but I can tell you that there were no fender cross flags until October or November 1976. And after January 1977 the fender alarm switch was incorporated into the driver’s side key switch. The door trim tag is where you get the production date of the car.
So if you have:
No fender cross flags and just alarm key switch in fender its early production.
Cross flags on fender and alarm key switch in fender mid production.
Cross flags only on fender late production.
Brian

 

I might be able to give you some idea as to where your car is in the production run for 1977. My car has crossed flags on the fender and had the alarm key on the fender until I glassed it in. The production date on my car is February 25th 1977 and the last 6 digits on my VIN are 423927. I have the early style coolant recovery tank, early style parking lamp extension harnesses and early style T-Top weatherstrips. Whenever I order parts for my car and there's a choice of early or late model, mine always uses the early model parts. Hope this helps.

 

If you get the Vette Vues fact book, it will list the monthly vin numbers. My 77 is very early and has an orange block, most 77's were blue.

 

so what month makes it an early 77 and which a late?

 

The later 77's have different t-top weatherstripping... therefore different t-top frames...

 

Between August 23 and September 7, 1976, the Flint, Michigan Engine Assembly Plant changed the paint colors used on Corvette engines from orange to blue. Some early production 1977 Corvettes were still built with the orange painted engines..

 

Source :corvette Black Book
"Early In The Production, The Low-Fuel Light Warning Light Was Not Available, So Chevrolet Deleted It And Reduced The Cost Of The RPO ZX2 Convenience Group Option From $22.00 To $18.00. The Quanity Of Low-Fuel Light Deletes Was 3,881 Units"

TOTAL ZX2 OPTIONED UNITS WERE 40,872

 

Source: Corvette Black Book
"Effective With V.I.N. 1Z37X73427373, The Alarm Activator Was Moved From The Drivers-side Fender To The Drivers Side Door Lock.

 

Most Likely The "Early" To "Late" Model....Came In To Play Around The Middle Of March Of 1977.

 

Source : Corvette Black Book
Unit Production Dates.....

1976 Year Production
August #00001 To 02287
September #02288 To 06337
No October Listed
November # To 14216
December #14217 To 17551

1977 Production
January #17552 To 21118
Febuary #21119 To 24662
March #24663 To 29041
April #29042 To 33057
May #33058 To 37029
June # 37030 To 41233
July #41234 To 45179
August #45180 To 49213

 

Historic Date In 1977 :
On The 15th., Of March 1977 The St. Louis Plant Built The 500,000 Th. Corvette, A White Sport Coupe With Red Interior.

 

I wonder if I own it!!

(the 500,000th)

hehehe

 

Not sure if this is an indicator, but you can add the flat A/C compressor to the list of late 77. Not that some lates didn't have the big compressor, but if you have the flat one (original), I would say you have a late.

Tommy

 

Most people will say the cut off point between early vs late is at serial # 1Z37x7S427373 which is the point at which the alarm was moved from the drivers side fender to the drivers door lock. As well many changes before that sequence number, many changes were made after that sequence number. The change from 19 pin t-top seals to 18 pin occurred after that point. The VIR unit on the A/C was replaced by the newer dryer late in production. The integration of the tape ejection with the last preset button on the 8-track option was late in production. The early owner manuals will have an 'A' on the part number, later manuals had a 'B' and the later manuals reflected the change in the alarm system. There was a period after sequence number 427373 where the 'A' owner's manual was used and a paper insert was placed inside them to reflect the alarm change. The last change that was made very late in the '77 production year was the addition of the spare tire lamp to the convenience group. By the way, did you know that there was an early and late sale brochure for '77?. The early one had the moon roof option listed. When the deal failed with the supplier and that option was cancelled, GM had to produce another brochure. I have copies of both. Did you know that the very early '77 used the black brake booster which were left overs from '76 before going to the anodized finished ones.

 

My '77 was made in March of 1977. I don't know that there is a hard-fast rule as to early or late. I generally consider my car a late '77, as I have the late design T-Tops (the weatherstrip is different based on how many "clips/tabs" there are). However, my alarm switch is still on the fender.

However, I've found some things that seem to lend itself to early and some that lend itself to parts filtering in from the 78 model year.

Of course, all this assumes the car is factory correct and parts were not changed over time that altered that -- so you are going to have to evaluate it based on the parts your looking for. Call the vendors, they're usually willing to help you get the right part the first time.

It does matter for some parts, but I haven't found it to be too much of a sticking point over the last several years.

Brian.