[etd66ss]

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...

[poncho-mike]

It's getting late, so I just took a quick look at your photos.

As far as I know, the 72 GTO 400 automatics were usually YS codes, except for some late ones which were coded Y3. You need to get a photo of the heads and the back of the block near the distributor. The heads should be a 7K3, with the date code cast into the surface just below where the head meets the valve cover. The date code is formatted as a letter followed by three digits. A = January, B= Feb, etc. The next two digits are the days of the month, the last digit is the year. B121 is Feb 12, 1971. There will be cast dates on the intake, block, heads, and exhaust manifolds. The Grand Prixs, Formula 400s, Lemans and other variants with 400 4-barrel engines were all YS coded, so it would have been a high volume engine. I wouldn't expect the date to be very far off from the build date.

The TH400 is a 1970 model, code is PY. It obviously is not original. The VIN should be stamped into the side of the near where the tranny pan meets the body.

I think somebody stamped that VIN into the block. I am more into F-body, but I own a couple of early 70s F-bodies. In general, the VIN is usually much smaller only parts of the VIN is stamped into the block. On a 71 YE block I have, the VIN in the block is 21NXXXXXX, with 2 for Pontiac, 1 for 1971, N for Norwood, and the last six digits of the VIN. It's possible that different plans used different size VIN stamps, but it looks to me like somebody started stamping the digits in one at a time. On many engines, the VIN stamp will be deeper on either the bottom or the top because the stamp wasn't exactly perpendicular to the face of the block when the VIN was stamped in.

Other than that, you will find many experts who can answer your other questions.

Mike

[Baron Von Zeppelin]

You might also want to post a pic of your PHS Invoice

I'm looking at an actual Buildsheet for a 72 GTO 400cid 400 THM

It shows Engine Code = YS
Trans Code = PG

Don't know why PHS sheets are showing completely different info.
I'm also looking at same page as you from a 72 GTO PHS packet that is showing
YT engine / PX trans

WF is a 3.23 Single Trac Axle - you might still have the original unit there.

Your engine is a blatant blundered attempt at restamping the partial VIN .
I mean like completely screwed.
They tried to stamp a Full VIN

You still might have a "proper 72 GTO engine"
Just not the original.

Some of what like Mike was saying -
YS was also used many years - so you need the date code by distributor
It may be matching to the trans - and also be a 1970 YS with 13 Heads.

1972 heads should be 7K3 in big raised characters on the center exhaust ports
right above where the exhaust manifolds bolt to the head.

[etd66ss]

I scanned the PHS docs, can be downloaded here: https://drive.google.com/file/d/1eoK...ew?usp=sharing

The car has #62 heads on it now, the prev owner gave me the original 7K3 heads, I'll have to inspect them for date codes.

In the meantime, here are some more codes:

Intake casting:

https://imgur.com/pZwPS3Q

Intake date code:

https://imgur.com/mRkeonH

As far as the date code on the block, all I can make out is A30X, I can't read what the X is, it's too blobby to see the digit. It's definitly not a 0 or 1, it looks like it could be a 2.

The prev owner told me he was on the phone with PHS before he bought the car, explaining the odd stamping on the block, PHS told him it was legit. I guess I will have to call them and have the same conversation. If someone wanted to stamp this, they would have to machine the front of the block to remove the original stamping? They would have to machine off like 20/30 thou?

[etd66ss]

Also, I found the previous owners listing where he's stating it's the original block.

http://findclassicars.com/pontiac/53...in-kansas.html

I have an inquiry in with PHS, and PHS musclecars to see if they can comment.

['ol Pinion head]

The block stamping of the confidential vin is a amateur forgery.
-contains too many characters, as mentioned above
-too large of characters
-wrong font of characters

Personally own two '71 Pontiac plant built performance A-body builds, over the years have owned many more, also own two '72 Pontiac plant builds. Since last Thursday, while up north, have examined the faces of three other '72 Pontiac plant 400 & 455 blocks, as well as the one in a very special 71 (entire thread on that car on PY over the last few weeks). All of these '71 and 72 Pontiac plant usage engines had the same the distictive same size and font confidential VIN.

[etd66ss]

So did they fill the original stamping in or machine the front of the block? I guess it's a good thing I did not spend #'s matching money for the car.

['ol Pinion head]

Anything is possible, with the carlot buiilder crowd, it's actually amusing in a way, as '72 YS blocks are relatively common. They have just got to play with their cheap stamp sets and lie through their teeth... For the carlot builder bunch, would not be that hard to find a 72 YS that dated the car's build, but that's work and added expense.

The late '72 model usage Y3 400 blocks are one of the missing '72 engine codes Rocky and I confirmed in the late 90's, early 00's... seldom run across '72 Y3 coded short blocks or bare blocks.

[etd66ss]

From the PHS doc's, this car supposedly came with a YT block, not a YS. The only weird part is the doc's also show the car coming with a PX TH400 and not a PG. From my info, the PX trans was not on LeMans/GTO, it was a Grand Prix trans.

['ol Pinion head]

If PHS notes YT, that's what your '72 GTO had in it. From what I've seen, each of the 72 model 400 4bbl/turbo 400 engine codes were installed in A, B, F, and GP models. YS, YT, and Y3 coded 400's were thus used depending on the period of production.

By far the most of those '72 usage 400 4 bbl coded engines & shortblocks I've owned (or examined & did not pull) were ones coded YS, out of early '72 model GP's. My only current '72 400 car project is a '72 LeMans Coupe built with a WK 400 & a Muncie. During my years as a core buyer pulling 400 shortblock cores, also had one or two '72 Y3's. Would have to go back through all my old log books as I wrote down two letter codes, block dates, assembly numbers and partial VINs on each. On YT coded 400's, have had two '68 400 Bird shortblocks with that code, as well as a bunch of '73-75 YT coded 400 block cores, can't remember having a '72 400 YT core, but am sure they were used.

Have no hands on info for the '72 T400 usage, have had many more '70-72 factory 455 equipped GPs, than have had same year 400 equipped GPs. Can relay many Internet sites do not have all the Pontiac ID codes listed or their correct usage.

[etd66ss]

OK, thanks for your help. At least the PHS doc's confirm it's a real GTO and not a clone.

[Baron Von Zeppelin]

If PHS notes YT, that's what your '72 GTO had in it.

OPH - he is just referring to the generic powertrain chart that comes with the PHS packet. Not an actual document like a BHC or Bsheet.
Have to think it is obviously flawed by listing YT as the only code.
-- it happens

Here is one for sample. [not his car]



Then here is an actual Buildsheet from a 72 400/400 - YS engine / PG trans

[Baron Von Zeppelin]

66ss - even if its luckily A302 casting date on block, its still too late of a date for a body date of 01A - to be in the hunt as original.

Probably just a little JB-Weld smeared over the original partial VIN on the block.
Then their big whop-pow with the new stamping.

YS is the right code

I cant see your picture well enough to tell if they goobered with the stampings up top as well.
But looks fairly acceptable from what "i can" see.
Wouldn't worry about much more of it - other than what you can establish.

The intake is dated way too late also.
At best - you could call it a "correctly coded" replacement engine - along with the 7K3's

[unruhjonny]

@ edt66ss;

I am incline to agree with BVZ on this one;
With the engine code changes from 1972-74 I am incline to suggest that the generic document is actually specifying the L78 which was intended to be used from the onset of the model year run;
any model year changes which necessitated or lead to a superceded L78 engine code would not be reflected in that documentation.

Be grateful that yours isn't a 1973 model year, I recently (for an acquaintance) went through figuring out which engine code (of the six) was correct for his TA.

I would like to go down a slight deer path because of this:



Was the font & partial vin style changed for 1972?

I suspected that this was a bogus stamp, because it does't match the pre-1972 stamps as far as font size and character count;



... but it seems to very closely resemble what the OP shared from his block.

but just to add to the confusion this is the partial vin from my 1972 YX block - it seems to adhere to the font size and character count from the older blocks I have:



Can anyone chime in on this one?

My hunch is that both the OP's YS partial vinand my WS partial vin are bogus.

[Baron Von Zeppelin]

More times than not -
you can find more knowledge on this forum - than at PHS.

None of us , are as smart as all of us

[Baron Von Zeppelin]

Johnny , i'm not confident i comprehend the question well enough.
Or which picture you want info about (obviously not OP pic tho)
Or what year model is what picture -

and what day is it anyway ?

One picture - One question maybe ? for us old fogey's
lol

[etd66ss]

So I talked to both PHS, and PHS Musclecars, they both say my car should be a YT block and a PX TH400, contradicting the info here.

They did say it is not the original block, but would not tell me the stamping is a forgery.

[Baron Von Zeppelin]

And they are both wrong
if not one in the same.

They are meager enough to trust the flawed powertrain chart


[ edit for clarity - wrong on the YT , Tranny i don't care either way ]

[unruhjonny]

@ etd66ss

They are probable both citing the same reference material.

By all means ignore the information offered here - but do so at your own peril.

The sheer magnitude of seriously great information here simply cannot be stressed - it's people like BVZ who figure out information that eventually finds it's way to print.

[unruhjonny]

Originally Posted by Baron Von Zeppelin

Johnny , i'm not confident i comprehend the question well enough.
Or which picture you want info about (obviously not OP pic tho)
Or what year model is what picture -

and what day is it anyway ?

One picture - One question maybe ? for us old fogey's
lol

sorry.
I try to break down my word-y posts in such a way that they're easier to digest;

Is this partial vin stamp not one stamped at a Pontiac engine/assembly plant back in 1972?



It appears to have the same style and size font as the OP's engine... which i have put into question as authentic.