Engine casting number shows 1978??

[Ribbedroof]

Pretty low VIN, could be an early car.

Look for a 3 digit group on the cowl tag (if it didn't melt) in the format of numeral numeral letter. Numerals tell you month 01-12 Letter is week of month A-E

Forgot to add...FWIW, generally accepted dates for casting numbers to be "correct" for a given car are within the preceding 6 months of the build date of the car...at least on musclecar era stuff

 

[Texas82GP]

Is the VIN suffix stamped somewhere on the 3.8 block?

 

[HAFROD]

Alright, here is the cowl tag and a couple are hard to read. So I hope they make sense to somebody
79 4AE87 Z 088847
24C AM6 22L 22U
11C 19B 660059

 

[Texas82GP]

This might help confirm if the block is original to the car. Skip to the second post (first response).....
https://turbobuick.com/threads/engine-and-transmission-vin-stamping.363489/

 

[axisg]

Damn thought I had it
http://www.buickgod.com/article/3443.html

looks like this matches the vin instead of the cowl tag

 

[axisg]

Damn thought I had it
http://www.buickgod.com/article/3443.html

 

[Red78Calais4speed]

79 4AE87 Z 088847
24C AM6 22L 22U
11C 19B 660059

The 11C on your cowl tag shows the car was built in the third week of November (1978).

 

[ssn696]

Mildly related tale...

The door sticker is a bummer to lose. New Mexico DMV mandates two matching VINs on the car to prove it's legal. The door tag had been scraped off when the car had been painted by the PO. To get the wagon title transferred, I had to present the dealer paper the PO had kindly tucked into the glove box. It saved my bacon. The cowl tag has a six-digit body number (upper right) that matched the dealer paper; it also had the VIN printed on it - so now I had an indirect way to get two VINs...

I have a Chevrolet book that translates all those cowl tag codes. Middle row is paint code. '4AE87' doesn't happen match the block stamp, does it?

 

[Red78Calais4speed]

Now that I look at it closely, I think you misread the top line of the cowl tag. I think it should read:
79 4AG87 Z 088847
It decodes as following:
79 - the model year 1979
4AG87 - Buick Century 2-door sport coupe
Z - the assembly plant (Fremont, CA)
088847 - production sequence #
If you look at the build sheet you will see the sequence #088847 is listed in the upper lefthand box (#1) and the 4AG87 is in the upper righthand box (#9). I believe the Turbo Coupe option was only available on the Century sport coupe (AG87) and not the Century Special coupe (AE87).

 

[Red78Calais4speed]

A book that might be of interest is: Catalog of American Car ID Numbers 1970-79. It was put out by Cars&Parts magazine around 1990. It is soft bound with a red cover. It shows how to decode the cowl tags of all American cars built in the 1970's. There is also a catalog for 1960-69, as well as 1950-59. It will decode the door sticker on all Ford products, too. Sorry, if I said the F-word. There are several copies of each catalog on eBay right now. Just checked. Doubt if they're still in print. Probably won't find them in any bookstores.