# 65 Gas Tank Vent



## Glenellyngary (Sep 22, 2019)

When the car cam back from the bod shop the gas tank vent was in a box of parts. Would someone PLEASE post pictures of the vent mounted in the car with a description of where it goes.
Thanks in advance


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## PontiacJim (Dec 29, 2012)

Neat little feature above on this site is the "Search Community" search engine which will pull up a ton of assorted past/present posts. Just type in what you are looking for and see if it has already been covered. I typed in Gas Tank Vent and got many hits. Here is one that will help.









gas tank vent


pulled tank out of my 65 gto. was leaking where neck connected to tank. tank looks pretty new. there is a vent tube in side of filler neck with no connections. sending unit has a 1/4 inch tube that is capped.is an air car, but not useable. should either of these vents be used. motor is a 455...




www.gtoforum.com





Also suggest you purchase a Chassis Manual for your year car as this will be a big help as well. Some other books will help with restorations. Check it out here:









FAQ - General: GTO and Pontiac Reference Sources


Surprised this has not been brought up - a suggested reading list for us Pontiac enthusiasts. Let's list any books, journals, factory literature, CD's, or other printed materials tht may be of value. And, it does not have to necessarily be Pontiac specific if it can be applied to out hobby...




www.gtoforum.com


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## Glenellyngary (Sep 22, 2019)

yeah, been there over an hour, that's where I found this, where is the location in the car?

since it has an grommet and a clip to secure it it is obviously in a double panel, where?

I installed the II Much system in my LS2 Camaro but figured I'd try this first.


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## GTOJUNIOR (Aug 7, 2011)

Open your deck/trunk lid and look down inside. 
This vent is attached just under the rear center support brace on the passenger side.
There should be an approx 2" hole on the upper floor pan for the grommet to be set into.


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## Glenellyngary (Sep 22, 2019)

Thank-You GTO JUNIOR, the info YOU provided is VERY Helpful.

The Chassis Manual I purchased in 1999 does not have this info. See below. Same page pasted as you provided, noticed the info you provided is from a 67 manual.

In 1999 there wasn't a fraction of the information or reproduction parts available as many of you are aware nor was the internet anywhere as helpful or misleading as today.


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## Glenellyngary (Sep 22, 2019)

Forgot to mention, the car was in "Paint Jail" for 6-years. The trunk pan (no holes for the vent), a small patch on the rear quarter and the drivers floor has a patch at the gas pedal area. Hence the gas pedal pin placement issue which has been resolved via helpful members of this site and the gas tank vent questions.
The car was in a barn in the Dallas area for 27-years (what I was Told and it looked like it), had the original shocks and exhaust among other original deteriorated parts. The driveshaft was in the interior, the convertible top was all but gone, it was so nasty my wife didn't talk to me about the car for 6 months.
My 3 daughters and I spent 7-years (including Paint Jail) restoring it. When purchased it had 27k miles, it now has 44k miles and getting ready to sell it it to someone else that will appreciate it as much as we have.
Almost forgot, pictures of it have been used in 3 magazine articles that I am aware of over the years.

To the HELPFUL members of this site a BIG THANK-YOU!


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## Banjos (May 10, 2021)

My '65 Lemans doesn't have a vent tube that passes through the trunk floor. It has a little vent tube that stays just above the tank fill neck. I don't even have a hole in the trunk floor for what is pictured above. I never knew there was a different set up out there... how common is either set up? The things I learn reading this forum.


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## PontiacJim (Dec 29, 2012)

Banjos said:


> My '65 Lemans doesn't have a vent tube that passes through the trunk floor. It has a little vent tube that stays just above the tank fill neck. I don't even have a hole in the trunk floor for what is pictured above. I never knew there was a different set up out there... how common is either set up? The things I learn reading this forum.



Here is 1968, upper right hand corner is Tempest/Lemans/GTO from the Chassis Manual. This looks more like what you have described on your fill neck. Tank also has a vent in front corner as seen in the upper left - believe 1968 and up design. Gran Prix and full size use a different set-up going through the trunk.


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## GTOJUNIOR (Aug 7, 2011)

HOLD THE PRESS!
Finally made my way over to the shop and first have to admit I learned something.
My first post was based on '66 which I ASSUMED  was the same. It is not.
To make matters worst there is conflicting information on the internet, go figure. 
Even some of the parts suppliers have vents listed incorrectly as 64-67.

That said I'm still not 100% sure if there was a late-year design change in '65
but can say all the '65's at the shop have the filler neck vent tube layout/design as BANJOS described.
My humble apologies for leaping before looking.✌


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## Glenellyngary (Sep 22, 2019)

I also have just the tabs. My car is an early, 3rd week September, serial number 1908. When my car was in the body shop there was another 65 GTO, it is possible the vent assembly isn't even from my car. 
Is there data available to know of the first 1,908 Pontiacs produced for the 65 model how many were GTO’s?
Is there data to know the date production began for the 65 model year?


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## O52 (Jan 27, 2019)

General production started on Aug 24 1964 but each plant had its own start up date and production serial numbers. And for 65 the GTO was still considered a LeMans, so the 1908 figure would include the LeMans.


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## Glenellyngary (Sep 22, 2019)

So my car is number 1,908 of those produced at the Fremont plant including Lemans and Tempests of various models to include hardtops, sedans and convertibles?

Thanks for the info.


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## O52 (Jan 27, 2019)

Is the 1908 number part of the VIN or from the Fisher Body plate?
If it's from the VIN that would include all V8 models


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## Glenellyngary (Sep 22, 2019)

O52 said:


> Is the 1908 number part of the VIN or from the Fisher Body plate?
> If it's from the VIN that would include all V8 models


The VIN.
I assume the block was manufactured July 8th?








Can you tell me what the stamped numbers above the YR represent?


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## O52 (Jan 27, 2019)

Looks like July 9, 1964

The number above the code is the Engine Unit Number or EUN, also known as the MUN. 
A sequential number of engines built (starting at 000001) during the model year. Used for warranty and recall purposes. 
The YR code for 65 designates a 360 HP, automatic, Tri-power engine. 

With that being said, your EUN does not appear to correspond with the casting date. The number and the two letter code were stamped during engine assembly at the Pontiac engine plant. Approximately 2500 engines a day were assembled which given your engine casting date, should be very low. 
664441 would place the engine assembly date in April or May. 

Now strange things do happen. It is possible that this particular block was left in a corner somewhere or damaged during the casting process (as was mine) and was never assembled until Apr/May of 65 _and_ your original engine was replaced at one time with this one. 

Do you have a photo of the Fisher Body Plate?






EUN or MUN and how do they work? - PY Online Forums - Bringing the Pontiac Hobby Together


EUN or MUN and how do they work? 64-65 GTO Tempest & LeMans TECH



forums.maxperformanceinc.com


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## Glenellyngary (Sep 22, 2019)




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## Glenellyngary (Sep 22, 2019)

Here's what I know (remember) about this car when I bought it in 1999.

PHS documentation: 
Born as a 4bbl 389 auto, delivered to Van Winkel Motors, Dallas, TX. 

The engine in it is what it came with, the tri-power was in the trunk. Tri-power was rebuilt by Mike Wasson, all the numbers on it were and are correct.
The numbers on the engine have puzzled me for years, perhaps as you suggest it is a warranty replacement, is it possible the customer upgraded the engine at that time? No paper trail.

As noted above, it is a TX car which was in a barn for 27-years and it showed. The main reason we dedicated the time and money to restore it is a AC Convertible. From what I have found there were only 1,000 / 1,100 produced.


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## Glenellyngary (Sep 22, 2019)

Forgot to mention, when we got it it had an Edelbrock intake and a Holley carb.


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## O52 (Jan 27, 2019)

If they could only talk eh? 

Do you have the date codes and numbers of the cylinder heads? I think on older engines they're under the valve covers.


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## Glenellyngary (Sep 22, 2019)

Not in the position to pull the valve covers, broken hand.


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## Glenellyngary (Sep 22, 2019)

Did GM add any markings to warranty engines that you are aware of? Per the post you provided the link to:

"In '64, they assembled approximately 615,000 units. I don't know the '65 total but think it was higher than '64. Typically they churned out something like 2500 motors per production day. So the count went up quickly".

Now the EUN numbers stamped on the engine are really making me scratch my head. EUN and date code would suggest it was a forgotten casting. Is that a reasonable assumption?


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## O52 (Jan 27, 2019)

Reasonable. IIRC for warranty work the block would have an SR stamp (service replacement).

Normally the engines are assembled within a few days of casting and depending on plant location installed in a car one to six weeks later. Pontiac assembly plant cars could have an engine installed just a few days after casting. Fremont, at least a week or more later. 
My numbers matching block was cast in March, assembled in late April, shipped to Fremont and installed in the car the first week of May. When I had the engine rebuilt the machinist noted damage to the cylinder deck surface that had been repaired. I have one cylinder head that was cast on Apr 22 the other was in February. The February head had damage that was repaired too. It would appear that my engine was assembled from left over parts. My EUN is also in the 600,000s which in my case was a late April build. 

It would be interesting to see the dates and numbers of your heads. Could possibly explain at least part of the mystery.


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## Glenellyngary (Sep 22, 2019)

Thanks for your time, in about 6-weeks I will pull the covers and provide that info.


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## O52 (Jan 27, 2019)

I went over to the Wallace racing website where they keep a record of EUNs, dates, engine codes. 
According to their database Pontiac was still building 64 engines in July of 64. 

Year. Code. Date Block. VIN. EUN Model Plant Build Date

1964925W-9773153M29606594700LeMansM-Kansas City MO07C326"196478XX-9773155F038224601943GTOF-Fremont07D389"196478XX-9773155-604711GTOF-Fremont07D389"196411HG649178155-605851Catalina--389"196476XW-9773155P297789610xxxGTOP-Pontiac-389 Tripower"196476XW 9773155 611661GTO  389 Tripower"196476XW-9773155-611673GTOK-Kansas Citybuild date 7/24/64389 Tripower"196476XWG1049773155-613043GTO--389 Tripower"196476XWJuly9773155 618467   389" 196476XW 9773155P291832619777GTOP-Pontiac07D389"


Now look at the Dates and EUN for the 65 engines. Your EUN falls in early July of 65. I wonder if the block casting date was set up incorrectly. Should be a 5 instead of a 4.


*Year**Engine Code**Engine Date Code**Block Casting Code**VIN**Engine Unit Number**Car Model**Plant**Body Build Date**Misc*1965WS 9778789Z116462329002GTOZ-Fremont3-13-65389"1965WSC259778789 343286GTOPontiac02D389"1965WSC559778789K122719365942GTOK-Kansas03C; 3-26-65389"1965YS 9778789K124775403874GTOK-Kansas City03D389"1965YS-9778789-413901GTO-04B389"1965YCD859778789P252802423543CatalinaP-Pontiac-389"1965WGD359778791 438908   421"1965WTD115  442162GTO 04B389"1965WS 9778789 453102GTO  389; 4/29/65 build date"1965WHD1459778791P272814470881Cat 2+2P-Pontiac-421 tripower"1965WGC1459778791 471754   421"1965WSE759778789 517250GTOP-Pontiac 389"1965YKD2859778791-519164---421 HO"1965YS 9778789 522575GTO  389"1965YD---536631---400"1965WSE1959778789 537418GTOP-Pontiac05C389"1965WT-9778777P303522555218GTOP-Pontiac-389"1965WEE2759778789D124433559185BonnevilleD-6-10-65 delivery date389"1965YN 9778840 570446Lemans  326"1965YDE2759778789 577414   389"1965WS 9778789P320839600938GTOP-Pontiac06C389"1965YSF1759778789Z129495610473GTOZ-Fremont6D389"1965WS 9778789P328853623479GTOP-Pontiac06D389"1965YS-9778789P341247656178GTOP-Pontiac389"1965WSG1759778789 701080GTO  389"


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## O52 (Jan 27, 2019)

__





Wallace Racing's Pontiac Engine Unit Number Search






www.wallaceracing.com


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## Glenellyngary (Sep 22, 2019)

That would make sense, a lot of what if's.


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## PontiacJim (Dec 29, 2012)

My take on the Data tag is - this is a 1964 Data tag which still uses the "Magic Mirror" script which was deleted/changed for at some point in 1965. So this would also indicate an early build which your car is - September 1964 and is a 1965 year model. So I am using some info from the Fremont Chevelle manufacturing line that may apply here.

Upper left corner - 9C means September, Third week. This is when Fisher Body completed the body and it went to the factory for final assembly on the assembly line. A note from the Corvair site, "There is a definite time interval between when the body was completed and delivered and when the car was finished on the Chevy side and a VIN number assigned. This was usually within a week or two, but sometimes could be longer. This system gives rise to the possibility of a body built date at the end of one month and a final production date at the start of the subsequent month. Fisher would also deliver bodies in groups and was known to sometimes hold back bodies for one reason or another, so it is possible to have cars bodies that are out of sequence with the VIN numbers. (i.e. body 8 has a Vin # higher than body 12)."

From the Fremont 1964 Chevelle website -"The upper right hand corner also contains a dashed number (such as 3-1) that correlates with the Fisher Body job number."

BF = Fremont and the "96" is said to be the in-plant sequencing number and an unknown.

Trim - 218 3E = Parchment (seats), Black (door - lower carpet), Parchment (door center panel), Parchment (Headliner, "Whipcord" perforated), Black (floor carpet).

Paint - Y1 A = Y=Maifair Mayze, 1=Standard GM color, not a Pontiac color, A=Starlight Black pin stripe color.

U.P.C. codes were used by Fremont for their Accessory Codes, not the 5 Group Code System. Your tag does not seem to have any shown.

From the Fremont 1964 Chevelle website - "On the right side of the fourth line is a 2- to 5-character number corresponding to the manifest sequence number from production broadcast notice."

Might be me, but that YR almost looks like the "R" in the photo is stamped over an "S" as it may be the light, but looks like the bottom tail of the "S" between the lower legs of the "R". The "YS" engine is the 335HP version. I searched the web for a "YR" code and didn't really find a good photo of the letters. Found a 1973 350 "YR" stamped block and the "R" looked different, but it could have been the year or factory stamp that made the difference.


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## Glenellyngary (Sep 22, 2019)

Thanks for the info Jim, really in-depth.
And the mystery continues, my curiosity got the best of me and I "Single Handedly" (or 1 1/2 handedly) pulled the covers. Not sure I can get them back on at this time.
Drivers side:









Passengers:









When rebuilding the heads there was a pulled stud so I had the shop add screw-in studs.

Original block and replacement heads? Replacement everything? Period correct?


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## O52 (Jan 27, 2019)

Replacement everything. The heads are dated at the same time as the block so are probably original to the block.
But... The engine was assembled 10 months after your car was built but still a 65.

The heads are code '76'




__





Pontiac V8 Cylinder Heads






wallaceracing.com




76 heads were mounted on 389s
290 HP YD code,
325 HP YE code
333 HP WE code
and a 421
338 HP YH code
The valve sizes and compression is the same as a GTO '77' head so no real difference

After blowing up the photo of your engine code it appears to be as Jim mentioned; a re-stamped YR.











But I think the previous code was a YD, a 290 HP 2 bbl engine which would match the heads. More than likely the engine is from a Catalina. A dealership would not have used this engine as a warranty replacement.

This is my opinion of course, others may see it differently

From Wallace Racing;
*Year: *1965
*Engine: *389
*HP: *290
*Engine code: *YD
*Trans: *A
*CR: *10.5
*Cam: *066 * 
Head Code: *76 (9778776)
*BBL: *2
*Carb No: *27025060/61
*Misc:*
A/C Block Casting # 9778789 Should have full head production number under valve cover - 9778776


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## Glenellyngary (Sep 22, 2019)

Only 1 problem with that thought. The casting date G94 on the block is a year after the casting numbers on the heads. I do not disagree the "R" appears that it could be stamped over, was it a YS (which would be correct for the car) or a YB, YC, YD, YE or YG or is it an YR with a suspicious 
machining line / scratch? 
Guess the only thing positive is it is a 389, the block casting date is correct for the car (markings are suspect), the heads have been replaced and a numbers correct Tri-power was added somewhere along the way.
In the end a 65 Numbers Matching car is all about casted and or stamped numbers, there isn't serial numbers tying any of the drivetrain to the car.


389​256​*WA,WB*,YA,YB​389​290​*WC*,YC,YD​389​325​YE,YF​389​333​*WE*​389​335​*WT*,YS​389​338​*WF*,YG​389​360​*WS*,YR​
Not sure there is reliable data anywhere, reviewing info on the Wallace site or on the engines to know what is real. See below copied and pasted from the Wallace site:


1964925W-9773153M29606594700LeMansM-Kansas City MO07C326"

196476XW-9773155-611673GTOK-Kansas Citybuild date 7/24/64389 Tripower"

2 cars built at the same plant within a week of each other and the the EUN numbers are 16,973 apart, if you look at the early 65 builds there are engines with K and L 64 castings so it would appear there were more castings available than cars to put them in.


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## PontiacJim (Dec 29, 2012)

So it boils down to this - The engine, in my opinion, has been restamped. From my internet searching the EUN numbers in the "400" (Last 3 digits) were as pointed out stamped in April/May - so too late to be original to the car.

The heads are not GTO heads which would be the "77" castings, yours are the "76" castings. They were manufactured in July 1965 - not original, but same as the "77" castings.

The tri-power set-up is not original to the car, but previous owner went out of his way to do his best to provide a correct 1965 small center carb set-up and matching dates to your car.

The PHS documents provide the original engine/trans with your car no longer having its original engine which is not uncommon. Enjoy the car for what it is now. No one will care once you put the tri-power on it - until you sell the car and for many, original is not that important unless the rest of the car is original, or restored to be original using original/NOS parts.


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## Glenellyngary (Sep 22, 2019)

I can't agree with you more.

On another note, what is the breakdown on the EUN. Is there a breakdown to the 6 numbers that specify build / assembly dates?

Thanks for your help in figuring out what is in this car.


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## O52 (Jan 27, 2019)

The EUN is model year sequential starting with 000001 and the number depended on many engines were needed for the year. So that number changes year to year with respect to a date. On years of high production you'll see 600,000 plus in April such as mine in model year 1968. In model year 1965, 600,000 plus wasn't obtained until July '65. I'm sure the Firebird was responsible for the increased production in 68 and after. 
Since Wallace maintains a partial database of EUNs to casting/assembly dates you can get an idea of how that changes year to year.

The EUN was how Pontiac kept track of the engines. It was listed on your warranty card. Whenever you needed warranty work the dealer would verify the engine EUN against the warranty card EUN. VINs were added to the engine block in 68 and together with the EUN, was used for warranty claims. 
I think an abbreviated EUN is found on the PHS paperwork on most pre 69 models. Not sure though since it wasn't listed on my 68's billing history card but I have seen other 68 billing history cards with it. Suppose it may have to do with whoever was keypunching the information at the factory.


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