# 68 engine code



## Layzdude (Jun 14, 2015)

I just bought a 68 hard top. The guy I bought it from had the original build sheet and the car is coded as a 4 bbl 4speed. He was not sure if it was the original motor. The engine vin has a WT in front of the serial # with a YD underneath. 
Any thoughts would be helpful.


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## Pinion head (Jan 3, 2015)

Welcome to the board. The block is a YD coded 389 or 400, Pontiac V8 blocks were not stamped at plant 9 (engine assembly plant) with two or 3 letter code before the assembly number. Appears someone has used some sort of generic stamps and stamped very lightly the letter WT. 

To find out what year 389 or 400 block, will need to look at the block casting date cast into block in the area behind the distributor hole. The block casting date will be alphanumeric, examples: 

J015 = October 1, 1965
M106 = Dec 6th, 1966 (the letter I was skipped for Sept this year)
A310= January 31st, 1970

There are also block casting numbers and head casting numbers that we can delve into more, but the block casting date will help nail down what year of 389 or 400 big car block has been installed.


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## Layzdude (Jun 14, 2015)

Thanks for the reply. Thats what I expected. Was holding out hope that it was the original motor. But not a big deal to me. As long as it's a Pontiac big block. I won't get a chance to investigate more until after the weekend.


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## 05GTO (Oct 6, 2004)

Layzdude,

Welcome to the forum, 

The block appears to be a late year 69 / 70 400 or a late year 72 / 73 455, the casting number behind the #8 cylinder should be 9790071 (69), 9799914 (70) or 485428 for both 72 & 73.

Definitely not a 389 or a 67 400 according to the engine unit number, 

btw, unlike Olds and Chevy, Pontiac did not identify their blocks as big or small, all Pontiac blocks used in the A and B-bodies from the 326 to the 455 were the same size with a slight weight difference.


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## Pinion head (Jan 3, 2015)

05GTO said:


> Layzdude,
> 
> Welcome to the forum,
> 
> ...


Not a production '72 or '73 455 as the assembly number does not start with a *(*


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## Layzdude (Jun 14, 2015)

05GTO said:


> Layzdude,
> 
> Welcome to the forum,
> 
> ...


Thanks 05GTO did not know Pontiac did not differentiate between big block or small block


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## 05GTO (Oct 6, 2004)

Pinion head said:


> Not a production '72 or '73 455 as the assembly number does not start with a *(*


Pontiac didn't start using *(* until 73 so it could be a 72, do you think it is a 389?


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## Pinion head (Jan 3, 2015)

05GTO said:


> Pontiac didn't start using *(* until 73 so it could be a 72, do you think it is a 389?


The *(* as the beginning of the assembly number began appearing with late '70 model blocks cast in June of 70 and also is evident on very early '71 HO blocks cast in E of '70. Some believe its a chipped 0 in the gangstamp tool. The *(* continued on blocks up through '74 production.


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## Layzdude (Jun 14, 2015)

The guy I bought the car from said it was a 400. He made it a quasi ram air by opening the hood and adding ram air manifolds. Not sure if that info helps.


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## 05GTO (Oct 6, 2004)

If it is a 400 it was originally a 2bbl engine with an automatic transmission and 290 hp. Both blocks were originally supplied with small valve heads.


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## BearGFR (Aug 25, 2008)

Agree with all the comments thus far. To get a positive ID on any Pontiac you have to start with the date code near the distributor. This is because the same 2-character engine code on the front of the block was in some cases used in multiple years on significantly different engines. Google up various combinations of "Pontiac Engine Codes" and you should be able to find several sites that show you how to decode everything, along with graphics/photos of where to find the codes in various years.

Bear


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## Layzdude (Jun 14, 2015)

Thanks for all the help. I will see what I can come up with. I took a really quick look around the distributor but could not see any numbers. Where should I look I tried google but it did not help!

thanks


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## PontiacJim (Dec 29, 2012)

Layzdude said:


> Thanks for all the help. I will see what I can come up with. I took a really quick look around the distributor but could not see any numbers. Where should I look I tried google but it did not help!
> 
> thanks


Google has everything! :thumbsup: How to identify your Pontiac engine

It may be covered up with sludge. To uncover, Google "degreaser," "wire brush," "rags," and "_elbow grease_." That should brighten those date codes right up for you and make 'em pop right out.:lol:


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## Layzdude (Jun 14, 2015)

Thanks for all the help guys. I will let you know what I find out


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## Layzdude (Jun 14, 2015)

I was finally able to spend a little time on the car today and the code I found behind the #8 cylinder next to the distributor was (9790071) according to GTO Alley website it is either for a 68 or 69 motor but neither off those years had a YD code. Any thoughts?


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## Pinion head (Jan 3, 2015)

Layzdude said:


> I was finally able to spend a little time on the car today and the code I found behind the #8 cylinder next to the distributor was (9790071) according to GTO Alley website it is either for a 68 or 69 motor but neither off those years had a YD code. Any thoughts?


A '69 YD 400 is the base 400 2bbl engine that was put in a ton of 400 2bbl automatic Catalina's and Executives. Same code and B body application for 1970. Nothing wrong with building it up. 

GTO Alley most likely doesn't have the full list of engine ID codes. Most "code info" websites merely copyied the info Pete McCarthy published in the '70's in his first book then in he late '80's in his second book. Of course no credit to Pete  Since that time, numerous '72 and '76 model engine ID codes have been confirmed that are not listed in Pete's book, so even the best printed source is not totally complete.


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## BearGFR (Aug 25, 2008)

Gotta have that date code next to the distributor hole.

Bear


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## Layzdude (Jun 14, 2015)

Pinion head said:


> A '69 YD 400 is the base 400 2bbl engine that was put in a ton of 400 2bbl automatic Catalina's and Executives. Same code and B body application for 1970. Nothing wrong with building it up.
> 
> GTO Alley most likely doesn't have the full list of engine ID codes. Most "code info" websites merely copyied the info Pete McCarthy published in the '70's in his first book then in he late '80's in his second book. Of course no credit to Pete  Since that time, numerous '72 and '76 model engine ID codes have been confirmed that are not listed in Pete's book, so even the best printed source is not totally complete.


Thanks Pinion Head. Either way I am happy with the car. Happier that it is at least a period correct motor.


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## Layzdude (Jun 14, 2015)

BearGFR said:


> Gotta have that date code next to the distributor hole.
> 
> Bear


I will look tomorrow. Not that it matters but I like to know exactly what I have. 

I am currently decoding the trans. Looks like the Muncie main cast and tail cast housings are different years "68" and "63"respectivley. Also trying to figure out if its an M20, 21 or 22. Pretty sure it is not a 22.


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