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post #1 of 12 (permalink) Old 08-18-2018, 08:09 PM Thread Starter
 
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Help decode my 72 GTO

I'm might be looking to sell my 72 GTO, and I want to make sure it's is a #'s matching car before I list it as such. I have the PHS docs from the previous owner, and he insisted it was all original drivetrain.

Here is the trim tag:

https://imgur.com/L66582m

Engine code:

https://imgur.com/vQ6lqoE

Engine VIN (seems to be missing last 4 digits):

https://imgur.com/YmKvLQT

TH400 Identification plate:

https://imgur.com/02sVagE

TH400 stamping:

https://imgur.com/QqsOo9J

Axle code:

https://imgur.com/p53hzFb

I'm not seeing in the PHS docs how to ensure all these components are correct... The PHS docs say the engine is a YT, but my block is stamped YS, which is 1971. The trans seems to decode as 1971 as well? It's a first week of January build, could they have used a 1971 drivetrain?

I know GM had a strike in 72 and the GTO production numbers were really low, and I heard they scavenged for parts etc...

Last edited by etd66ss; 08-18-2018 at 08:59 PM.
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post #2 of 12 (permalink) Old 08-18-2018, 09:25 PM
 
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Originally Posted by etd66ss View Post
I'm might be looking to sell my 72 GTO, and I want to make sure it's is a #'s matching car before I list it as such. I have the PHS docs from the previous owner, and he insisted it was all original drivetrain.

Here is the trim tag:

https://imgur.com/L66582m

Engine code:

https://imgur.com/vQ6lqoE

Engine VIN (seems to be missing last 4 digits):

https://imgur.com/YmKvLQT

TH400 Identification plate:

https://imgur.com/02sVagE

TH400 stamping:

https://imgur.com/QqsOo9J

Axle code:

https://imgur.com/p53hzFb

I'm not seeing in the PHS docs how to ensure all these components are correct... The PHS docs say the engine is a YT, but my block is stamped YS, which is 1971. The trans seems to decode as 1971 as well? It's a first week of January build, could they have used a 1971 drivetrain?

I know GM had a strike in 72 and the GTO production numbers were really low, and I heard they scavenged for parts etc...
Data tag is too blurry, but matches a 1972. The GTO was an option on the LeMans, Option Code W62.

Here is what my books say:
1972 GTO 2 Dr Ht Coupe - 5,673 made

YS for 1972 is the 400CI/Automatic. There is no YT for 1972.

Engine/Vin Number reads: 2=Pontiac D=LeMans 37+ 2-Dr Ht Coupe T=400CI 4 bbl carb Dual exhaust 2=Model year 1972 P=Pontiac, MI assembly plant 14= should be partial numbers of your VIN, but not complete. So if all that matches your VIN at the windshield, then I would say matching engine.

Heads should be 7K3 found on center exhaust port. This is the 250HP engine.

Axle code WFP is 3.23 ratio

TH400 should have a code "PG" which yours does not. Should also be stamped with your cars Vin. I see "PY" (V8-400 4 Bar. carb., GTO, LeMans, Firebird) which is listed for 1971 and was standard on 3.55-4.33 rear end ratios - so it may have the higher line pressure for firmer shifts. I would say it has been swapped. I believe it to be a 1970 transmission according to the date stamp "70" and the 20P of the serial number stamping with the "0" meaning 1970. It may have been a late 1970 trans installed in a 1971 car based on the "PY" code. Here is where I got this info: 1962-74 Pontiac Automatic Transmission Codes
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post #3 of 12 (permalink) Old 08-18-2018, 09:35 PM Thread Starter
 
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Quote:
Originally Posted by PontiacJim View Post
Data tag is too blurry, but matches a 1972. The GTO was an option on the LeMans, Option Code W62.

Here is what my books say:
1972 GTO 2 Dr Ht Coupe - 5,673 made

YS for 1972 is the 400CI/Automatic. There is no YT for 1972.

Engine/Vin Number reads: 2=Pontiac D=LeMans 37+ 2-Dr Ht Coupe T=400CI 4 bbl carb Dual exhaust 2=Model year 1972 P=Pontiac, MI assembly plant 14= should be partial numbers of your VIN, but not complete. So if all that matches your VIN at the windshield, then I would say matching engine.

Heads should be 7K3 found on center exhaust port. This is the 250HP engine.

Axle code WFP is 3.23 ratio

TH400 should have a code "PG" which yours does not. Should also be stamped with your cars Vin. I see "PY" (V8-400 4 Bar. carb., GTO, LeMans, Firebird) which is listed for 1971 and was standard on 3.55-4.33 rear end ratios - so it may have the higher line pressure for firmer shifts. I would say it has been swapped. I believe it to be a 1970 transmission according to the date stamp "70" and the 20P of the serial number stamping with the "0" meaning 1970. It may have been a late 1970 trans installed in a 1971 car based on the "PY" code. Here is where I got this info: 1962-74 Pontiac Automatic Transmission Codes
Thank you!

So I should not list the car as #'s matching then, even though it looks like a #'s engine. The partial VIN on the engine does match the VIN of the car.

I'm looking at my PHS docs, where they highlight what my car came with, and it clearly shows a 400 4 bbl YT L78 engine with a PX M40 transmission. There is no YS on this powertrain chart at all for 1972. For the rear end, it states 3.55 gears for non AC, and 3.23 with AC. My car is an AC car.
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post #4 of 12 (permalink) Old 08-18-2018, 10:21 PM
 
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Very nice custom color. Metal Flake?
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post #5 of 12 (permalink) Old 08-18-2018, 10:39 PM
 
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Originally Posted by etd66ss View Post
Thank you!

So I should not list the car as #'s matching then, even though it looks like a #'s engine. The partial VIN on the engine does match the VIN of the car.

I'm looking at my PHS docs, where they highlight what my car came with, and it clearly shows a 400 4 bbl YT L78 engine with a PX M40 transmission. There is no YS on this powertrain chart at all for 1972. For the rear end, it states 3.55 gears for non AC, and 3.23 with AC. My car is an AC car.
Hmmm, very interesting. I am using the GTO Association of America ID Guide and it does not list the YT engine code BUT, when I go to the Wallace Pontiac engine codes, I do see a YT code for the 250HP 400: Pontiac Engine Codes

So next I pull up my Pontiac engine book by Pete McCarthy and here is what I find- Both engines are identical 250HP/automatics and are the only engines used in the A, B, F, & G model lines - or all body styles. Other engine codes are specific to just a model line or a couple of model lines. So the engine seems to be a common engine for 1972. Again, no YT code for 1971.

The next thing you need to do to answer a few questions is to look at the back of the block near the distributor. You will find the year (typically a 2 digit casting number) and the date code as to when the block was cast. This should be close to your build date as should the date codes on the 7K3 heads.

I can't help much on the transmission other than what I have already provided.

I don't think all the plants went on strike, just the Norwood, Ohio plant which made the Firebird line. I don't think it affected the A-body Lemans. I read that to get as many as they could out the door after the strike ended and before the 1973 year models came out, they cut corners and did not undercoat them and just painted the exterior. I looked at a 1972 Firebird Formula 400 that a guy wanted to sell cheap, but was rusted very badly from the inside out - door jams were blowing out, so it made sense that they just threw these cars together. It really needed a complete body to save it. https://www.nytimes.com/1972/09/28/a...-174-days.html

I would contact PHS noting your build sheet and what you have found with your car. He would be better qualified to give you a definitive answer as he has seen build sheets that don't seem to match for one reason or another.

It seems odd that the engine appears to match the car, yet has the wrong letter code. Possibly the block was mis-stamped or the Pontiac paper is wrong, especially if there really is no difference in the engines.

So I would wait on PHS before advertising the car as original/non-original numbers. Also check the block dates.
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post #6 of 12 (permalink) Old 08-19-2018, 06:09 AM Thread Starter
 
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OK, so here are the intake numbers:

Casting:

https://imgur.com/pZwPS3Q

Date code:

https://imgur.com/mRkeonH

I can't get a good picture of the block date code, but looks to be A30X. Having a hard time distinquishing the last digit, it's not cast very well, looks like a big blob, could be a 2.

In the past have verified the block casting as 481988, but I don't have a picture, next time I jack up the car I'll try to get a pic.

When the prev owner had the engine rebuilt, he had #62 heads installed. I have the original 7K3 heads, will have to dig them out and get the casting numbers.

Bottom line is, how does all this effect value? I'm not sure a 72 GTO with a 250 HP 400 and a TH400 is a high dollar car anyways? It seems like it has the born with engine, and likely the born with rear end, but not the original trans, so not sure what to make of all this.
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post #7 of 12 (permalink) Old 08-20-2018, 03:22 AM Thread Starter
 
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On another Pontiac forum, I'm being told the partial VIN stamping on the block is a blatant failed re-stamping attempt by a scammer. Anyone else have any pictures of their 72 GTO block stamping?

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post #8 of 12 (permalink) Old 08-20-2018, 03:13 PM
 
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I think YS is a 2 barrel single exhaust engine and YT would be 4 barrel dual exhaust. Were GTO buyers still able to select a 2 barrel engine in 72?

The VIN stamp on the block does not look valid. Incorrect format and font.

You mention the engine has been rebuilt. Perhaps they found a suitable donor engine from a 2 barrel model and tried to transfer the VIN stamp?

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post #9 of 12 (permalink) Old 08-20-2018, 05:24 PM Thread Starter
 
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Quote:
Originally Posted by Shake-N-Bake View Post
I think YS is a 2 barrel single exhaust engine and YT would be 4 barrel dual exhaust. Were GTO buyers still able to select a 2 barrel engine in 72?

The VIN stamp on the block does not look valid. Incorrect format and font.

You mention the engine has been rebuilt. Perhaps they found a suitable donor engine from a 2 barrel model and tried to transfer the VIN stamp?

Sent from my SM-G930V using Tapatalk
PHS confirmed it's not the original engine.
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post #10 of 12 (permalink) Old 08-21-2018, 02:24 AM
 
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Originally Posted by etd66ss View Post
OK, so here are the intake numbers:

Casting:

https://imgur.com/pZwPS3Q

Date code:

https://imgur.com/mRkeonH

I can't get a good picture of the block date code, but looks to be A30X. Having a hard time distinquishing the last digit, it's not cast very well, looks like a big blob, could be a 2.

In the past have verified the block casting as 481988, but I don't have a picture, next time I jack up the car I'll try to get a pic.

When the prev owner had the engine rebuilt, he had #62 heads installed. I have the original 7K3 heads, will have to dig them out and get the casting numbers.

Bottom line is, how does all this effect value? I'm not sure a 72 GTO with a 250 HP 400 and a TH400 is a high dollar car anyways? It seems like it has the born with engine, and likely the born with rear end, but not the original trans, so not sure what to make of all this.

Looking at the GTO Restoration book on the 1972, the intake is correct for 1972. 1971 has a different casting number.

The 7k3 heads are correct for 1972.

Your block's VIN may be partially hidden under the timing cover and why you only see a few of the numbers. Keep in mind that that the letter code could be a mis-strike. It is possible that someone restamped the block, but I would have thought they would have gotten it right and restamped it "YT". Pontiac has been known to do some strange things. So I would not throw the baby out with the bath water just yet.

That engine code is really needed. You should also see the 2-digit year cast on the block next to the distributor hole, such as "71" or "72" depending on when cast. This was started in 1970, so you should find that as well. It may be the block has been changed out along with the transmission.

The trans listed for the '72 in the Restoration Guide also says "PX" is the same for 1971/1972, but it also shows where the VIN is stamped just as yours is and the VIN should be the last 8 of the car's VIN, so I would say your trans appears to have been swapped at any rate.
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