[John V.]

Greg, since the EUN is on the PHS, that is compelling.

If the block is original to the car, we already knew the VIN would be an anomaly.

John might be able to help figure out if the head dates are reasonable for the EUN using his EUN database. I don't know if he has good data for the Production Dates that builds were getting a particular EUN, but if so, that is the data that will help confirm "good" dates for the heads.

Since John is saying 10B as the earliest Time Built code for your EUN, I'm thinking Oct. 6th and 7th for the heads might be right in line with an engine assembled around Oct 10 and ready for installation in a 10B build so the head dates could be right. Except the engine assembly didn't go into a 10B build and for inexplicable reasons hung around in inventory until winding up in your May build.

A possible explanation, your engine was assembled and ran so poorly on natural gas in the engine plant, that your engine, originally destined for a 10B GTO, never got there and was plucked off the engine assembly line and set aside. Finally somebody fixed whatever was broken and put it back in inventory, whereupon it was placed back on the line and installed in your GTO in May. Whatever the case, it seems to be just an anomaly.

Greg, what about the cast date on the intake? I have seen lots of guys misread cast date tags on blocks, 5s look like 6s and so on. I believe the '68 cast iron intake manifold is the same 9794234 as used in '69? If you have misread the cast date on the intake, could be the intake was the problem that was fixed before it ever went into your GTO and would have a May date? Worth another look.

[dv657172]

Thanks Keith

[John V.]

Keith, thanks for the laugh!

Greg, that is a wide gap for '68 I think. By the mid '70s, the gaps became a lot less consistent, as the years went on wider spreads became more common by what I've come across.

The last of the Pontiac 400 blocks from what I remember learning years ago were cast in Nov. '77 and eventually found their way into the 400 powered TAs and Formulas built as late as May '79 IIRC. But of course that is a special case.

Is your EUN consistent with the cast date or did the block sit around awhile before becoming part of the engine assembly?

I once came across a block cast as I remember it in Feb '65. Somewhere I have details of this story but just going by memory at the moment. It did not involve a GTO. As I recall, it did not become part of an engine assembly until early in the '66 Model Year. Since the casting p/n hadn't changed, there was no reason for the block not to part of a "next model year" engine assembly but it seemed so illogical for a Feb cast block to have sat for that many months without becoming part of an engine assembly.

It was so unusual in my experience that I wondered if perhaps the cast date tag was a foundry mistake and that it was cast much later than the Feb date suggested by the cast date tag.

No way to know for sure but I just chalked it up to it being an anomaly that was out of step with what we typically see.

You might think it was a restamp but the evidence did not indicate that either.

In the end, it just "was". No need to draw any conclusion about it but it was fun for me to study that particular anomaly. Without knowing what is typical, I would not have known whether it was unusual or not. I'm fascinated by these and many other nos., so sue me!!!

[Greg Reid]

Originally Posted by John V.

Is your EUN consistent with the cast date or did the block sit around awhile before becoming part of the engine assembly?

I don't have the EUN handy but I'll post it tonight if I can remember. I know a lot of guys can ballpark build dates by EUN sequence but I'm not one of them. I'd be interested to see what you come up with in regard to that.

[Greg Reid]

It just occurred to me that it may not be a good idea to post the VIN and also, the fact that in '68 the EUN is listed on the PHS....so...if someone faked the partial VIN stamping, they would also have to fake the EUN stamping to match...correct?
They are both posted on the PHS and stamped on the engine.
So, I'm posting a photo of the EUN stamping..

[johnta1]

Greg, I have your eun submission, I would recheck your partial VIN on the block?

The date code and eun are good together.
But the VIN is way off compared to the eun.
If the VIN was 117 instead of 178 it would be good?
(or the block is from a 117xxx car)

The eun would be for a 10B (or something like B/C or D)

EUN Search

[johnta1]

My BHC shows the EUN which is 655492. Invoice date of car is 5/27/68. Block cast date would have been C118

Yours is around what Greg's should be.

[dv657172]

Have a Fremont built 65 GTO, numbers matching

Time Built Code = 06E, 5th week of June
Engine Cast Date = F265 = June 26th

Block definitely didnt sit around in inventory

By the way how did Pontiac define a week - Sunday at midnight to Saturday at midnight??

[Keith Seymore]

Originally Posted by dv657172

By the way how did Pontiac define a week - Sunday at midnight to Saturday at midnight??

Yes - I believe so.

K

[tempest1964]

Wel, all I can say is, that sounds very logical! Lol

[unruhjonny]

other than the cheifs comments, this is a great read!

I'm a numbers guy, not because I place great value in them but because I am fascinated by them

I am ABSOLUTELY with John on this point;
The genesis of my personal interest in this is that my car was purchased with a non-numbers, but correct model year/correct model engine...

[Rich-Tripower]

I have a car built the last week of December 1964 which was delivered to the dealership the first week of January 1965. The block is dated 12/11/64, one head is 11/11/64 one is 12/01/64. The engine was built 12/14/64, things sure moved along quickly. The transmission was built 12/22/64 and the rear end 12/10/64.

Interesting tidbits, it sure was delivered quickly! But more interesting is that the distributor was built 4/27/64. It sure sat on a shelf a long time.

[Greg Reid]

John V. ,
My EUN is 088529
I was wrong about the November date. The block is dated H167. The heads are J077 and J067... So August and October, not Oct and Nov.
Notice heads are one day apart yet a month and a half after the block.

[unruhjonny]

I have read that more often than not, block batches were were done in excess of head batches, so that more often the block casting date precedes the heads...

[Greg Reid]

The other weird thing about my car is that the intake has a '69 date. Not saying it's original but how often would an intake need to be changed for an identical piece?

[Tom Vaught]

If the Service People identified a serious Core Shift in the intake (potential intake leak) and they swapped it out for a different one.

We had a couple of cars come thru my uncle's Pontiac Dealership in the early 70 time frame with that issue. Tom V.

We had a LOT more issues with the Overhead Camshaft 6 cylinder bad heads vs that V-8 intake issue.

Tom V.

[Greg Reid]

I always assumed that the intake had been changed but still can't think of a very likely reason to.

[Greg Reid]

No John, I have never compared my numbers to others. I'm as certain as possible that the partial VIN isn't a restamp. Mainly because it's a base, auto with A/C GTO and has no special value and was priced as such.
If it was faked, the effort was wasted since the seller did not know that it was a matching numbers (block)...he was a Chevy guy and mistook the EUN for what he thought would have been the partial VIN. He got it from the original owner's mechanic shortly after the death, in his 80s, of that original purchasher. Again, if it was faked, someone along the short line of owners should have used that as a selling point after going through the trouble to re-stamp it.
I'll try to get a good pic of the partial VIN. Looks legit to me. No scratches, etc.
The heads and intake may have come from other cars...who knows? but I feel pretty confident that the block came with the car.

[PurelyGTO68]

It was hit and miss with the EUN in 1968. Some BHCs have it listed.....others are blank and some others just show a bunch of zeros.

My BHC shows the EUN which is 655492. Invoice date of car is 5/27/68. Block cast date would have been C118. 9792506 as cast vs ground and restamped.

Sent from my XT1585 using Tapatalk

[Greg Reid]

I just went out in my garage to check what I really already knew and the VIN is good John. It is the same on the VIN plate, the block and the frame rail...checked that when I replaced the trunk pan.
Also, as I said, the EUN and VIN are on my PHS Billing History. Weird, huh?

John V., interesting about the heads being more in line with the EUN than the block.

As for the intake, I just took another look an have to admit that the last digit is not clear...it looks like a 'I269' but could be 'I268'. Still doesn't help it's case for being original to the the car since it's after the car's build date either way.