[Spudkluppy]

...is the one you fail to ask.
I've been wrestling with asking this question since I joined the forum, hoping to avoid being embarrassed for asking such an "obvious" question. But searching online and in this forum I have found some conflicting answers.

The question?

What exactly ARE "matching numbers" and when/how are they important?

I have found threads online where this has actually started heated debates...some contend that it means different things if your talking MoPar vs Ford vs GM etc.

I basically want to know what "Numbers matching" means regarding my '69 GP...what numbers should match (and WHY) and where are they located on my car. And what is the downside if something doesnt match because I, for example, swap out heads on my XF block?

Thanks in advance...and stay tuned for more stupid questions...

[rustedgoat]

Stupid questions? Check out the lobby section, good amount of stupid questions and stupid answers.

Like you said there are different definitions. Mostly involving the casting number, date codes, factory stamped id codes and vin on components of the vehicle. For higher value collector cars it can have a huge effect on the resale value.

Some people feel "number matching" is factory born with parts other think if it appears correct it acceptable (as in restamped parts).

As far as your GP, if its not something special and looked for by collectors then just build it for yourself. Keep anything original that you unbolt from it.

[ra96]

Well the answer is this trem is very often used and-misused- ect- as stated above the big 3 and im sure overseas manufactures used part numbers and date codes these are sometimes stamped and sometimes cast and in the case of a lot of parts there is a date code even original body panels carry date codes
genericly speaking a car that is described as #'s match more often they are refering to the engine-trans and rear end orig to the car
not to overcomplicate but a true real all#'s match car will have parts like the wiper moter, voltage regulator , horn relay ect-- rebuilt or replaced or NOS with proper date codes
to simplify its always prefered to have or buy a #s match car -however in all due respect to everyone as far as value goes #'s match makes a major difference in a super perfomace cars -such as -hemi, superduty, ramair,chevy SS, shelbys ect
so far as- for example a pontiac (-again orig drivetrain is always better) so far as the 6cyl cars and the 350 cars the impact in value of non matching#'s is not as significant ( in all due respect)
that said-- lastly- if one is really searching for a #'s match car Reaserch the hell of it get every part# thats correct for it in a log and bring all the info with you when looking----- the bad side of this hobby is there are many sellers trying to fool you and just as many who really dont have the knowalge to give correct answers
there is Nothing Wrong with a great non matching #'s car
i hope this helps

[ra96]

To answer the second part of your question that becomes a personal thing to a degree and for sure a finacial thing
if your 69GP looks runs and drives fine even if the heads , block are the wrong # or date code-- youd spend a lot of $$ to replace them and the car would run the same -i must point out that as far as the block there can be as far as pontiac's of that vintage only 1 orig block- because - the last 6 digits of the vin are stamped in the block -a lot of guys shave the face of the block and re stamp the #s---- to me thats not orig #s match
So far as the added value to your GP well it would help a little bit but again once you start the #s and date code swapping game -where do you end?
In short so far as value the#s make the most difference in a superperfomance car as far as value

[ra96]

There are no stupid questions - this is a great place to to become more knowlageble about your pontiac and I for one think anyone who takes the time and $ to own a vintage car no matter what make or model thats a cool thing

[cuz68]

Like said above thay are no dumb ?s. I got my 68-GTO in 1974 it was 6 years old, And get this the engine had been changed to a 1967 big car B body car, I knowed nothing about codes or numbers back then, All i knowed was it was a very strong car that i have had a lot of fun in, I dont care about numbers. Be safe and have a lot of fun with the Old Pontiacs.

[mike nixon]

The local Dealer would replace warranty engines with low mile Salvage yard units, then collect the payment from GM for a new engine. From what I'm told that was a common practice in those years.

[2002Z4CSS]

Originally Posted by mike nixon

The local Dealer would replace warranty engines with low mile Salvage yard units, then collect the payment from GM for a new engine. From what I'm told that was a common practice in those years.

Sounds like fraud.

[The Boss]

To answer your question - in it's most basic form the block & trans are original to (born with) the car.

This can (& has) been expanded to mean everything to every engine component to brake boosters, steering boxes, A/C compressors, etc..

[Spudkluppy]

That (block/trans) sounds reasonable as to a minimum. But please, exactly WHERE on the block/trans are the numbers? And what are the numbers that need to match. Are they VIN related, or do the numbers match each other ... for example....would I find "12345" stamped on both block/trans?

As for the "expanded" parts...surely these parts don't have Numbers which match numbers found on the block, tranny, VIN, or cowl tag etc. right?

So would some kind of manufacturers mark, date code etc. be part of the elusive definition of a "True numbers matching" vehicle?

I guess ultimately the BUYER of any purported numbers matching car would be the person to decide if the numbers match his or her definition of a numbers matching car. I just would be hesitant to offer a car for sale as numbers matching not knowing if it meets the basic definition.

I ask because (obviously) I want to know if the car I bought is as it came from Pontiac
and also because what I do to the car kind of depends on its originality.

I plan on replacing the front suspension components which could easily be reconditioned and kept if a buyer down the road wanted to do a proper restoration. However, wouldn't internal engine or trans mods "ruin" the chance for a proper restoration?

This is a strong solid highly optioned SJ in a rare color and remarkable interior which may be of some interest in the coming years when the rest of the world runs out of GTO's, Camaro's etc . For now, I want to enjoy the car I've dreamed of having since it's debut (I was a Junior in HS) but I don't want to ruin it's potential (if that's even possible) by tearing into and modifying the drive train.

So, step one is finding out if my numbers match...

Thanks guys.

[428ho4spd]

First, you'll need a rag and a small putty knife or scraper to clean off the area of the engine block.

Standing in front of the car, the engine block VIN stamp it is located just to left of the of the timing cover. This will be stamped vertically and will start with 29P******, the last six will be the last six of the VIN.

For the trans VIN stamp... it is located on the driver's side of the car, it will be stamped into the case just above where the pan meets the case. These are a little harder to see and you will likely need some brake clean or solvent to clean off this area as it is porous.

The rear axle is a little different and has no VIN stamp... located on the driver's side axle tube, usually near the top close to the brake line is a date and usage stamp code. A wire brush works good to find these stamps. The date code will be a Julian Date... three digits = day of the year... 001 - 365. The two letter stamp code will be the usage code for your vehicle. Yours should be a 5F = 3.23 Limited Slip which was standard with a/c.

Component parts like heads, manifolds, alternators, regulators, starters, carbs, distributors, etc... will have date stamps and parts numbers. Depending on the particular part, how the car is optioned and engine & trans combo will determine what these stamps should be.

The big three are... the engine (including heads & manifolds), trans and rear axle are what most would consider a numbers matching definition. If you're selling a car, some may ask if the carb, distributor, alternator or other components are original to the car? Here you would need to check the stamp dates and part numbers to determine that.

Some front suspension parts have dates stamped into them, but I wouldn't consider saving any worn-out parts like tie rods, drag link or idler arm. On the engine & trans internal parts, some parts have to be changed during a rebuild and I wouldn't consider that to be an issue. Anything replaced can always be saved and kept with the car.

That is a special GP you've bought given the color and options. Have fun with it!

Grant

***Below is an example of a '69 GP engine and rear axle stamp***

[Spudkluppy]

Thanks Grant, for that well thought out and perfectly articulated response.

And pictures to boot!

Prior to making the purchase I saw the 7 digit number above the block code (XF) in the general area you say I should be looking...but it has no resemblance to my VIN.

The numbers and XF code were uncovered for the seller by a potential buyer (who may very well be a member of this forum) about a week before I made my decision to drive down to SoCal to inspect and ultimately buy the car.

So, should the VIN number stamping be near this "XF/7 digit" stamp? I haven't had a chance to look as I have the car parked at my mother in laws house across town and may not get to it til Monday.

Thanks, more to come....

[FrankieT/A]

The number with the VIN in the block runs vertically sometimes hard to read because the lower rad hose gets in the way.

Don't confuse numbers matching with "Date Correct".

Through out the service of the vehicle over many years, parts get changed. Like water pumps, alternators, starters, Etc. They would typically get replaced by Reman. stuff, in which the cores came off other cars, sometimes different years, sometimes off different car lines, like Oldsmobiles or Buicks. Remember a lot of times alternators, P/S pumps and A/C compressors are interchangeable between lines.

So, most importantly you want your block and trans housing to be "Numbers Matching". Everything else needs to be "Date Correct". It's always nice to have numbers matching, but unless its going to be a concourse restoration date correct is way less important.

Enjoy the car!

[The Boss]

Well said Frankie.

[428ho4spd]

Originally Posted by Spudkluppy

Thanks Grant, for that well thought out and perfectly articulated response.

And pictures to boot!

Prior to making the purchase I saw the 7 digit number above the block code (XF) in the general area you say I should be looking...but it has no resemblance to my VIN.

The numbers and XF code were uncovered for the seller by a potential buyer (who may very well be a member of this forum) about a week before I made my decision to drive down to SoCal to inspect and ultimately buy the car.

So, should the VIN number stamping be near this "XF/7 digit" stamp? I haven't had a chance to look as I have the car parked at my mother in laws house across town and may not get to it til Monday.

Thanks, more to come....

You're welcome... glad to help!

The numbers above the XF code is an engine block production serial number. On the older Pontiac's prior to VIN stamped engine blocks these numbers could be found the vehicle's Protect-O-Plate for warranty purposes and was a way to verify the engine was original to the car. Beginning in '68 I believe, they started stamping the blocks with the VIN and the POP's were no longer embossed with the engine serial number.

Your VIN stamp will actually be in the lower area on the block like in the photo, same side as the code stamp and behind where the lower radiator hose connects to the timing cover as Frankie T/A described. It will be much easier to see from underneath the car.

Grant

[69lm69gp]

I think numbers matching is most commonly used to discribe that car has orignal block and trans, and that can mean the engine and trans may have be rebuilt.

All orignal would mean ALL orignal, however the way it was explained to me is that this didn't include tires, not sure why. And some to people they my exempt other rubber parts as well.

Then there is concours where all the date codes are correct but the parts may not be orignal to the car.

[FrankieT/A]

Originally Posted by The Boss

Well said Frankie.

Thanks Boss