Engine and Chasis numbers

[tvmaster]

...so it pays to examine any '74-'75 closely! Lots of obvious clues for current owners, but if you don't know the cars...

It was the DMV fellow who explained to us how many number points were expected on the car, based on their massive vehicle database. Unlike the master mechanics/previous owners, at least he knew that the windshield VIN was missing. And he wasn't going thru menopause either....

 

[TomasL]

VIN plates on the windshield may be a North America only feature.

Well since some 15-20 years or so we have them here as well.

What is said is that the windshield plate and the enginebay plate is easily changed, just a piece of riveted aluminium plate, but the stamped number in the chassis is normally not that easy to replace, thats why its the only valid VIN.

On my Chrysler T&C it is located on one of the longitudinal beams under the car, obviously not that easy to forge/replace.
If you try to forge /replace it, it will be quite obvious.

 

[Dan Sarandrea (Phila)]

I guess that is the reason you never hear about "numbers matching" X1/9s like you do about most other cars.

[Please forgive me if you know this already...]

In the American muscle car collector market, the expression "matching numbers" means a lot more than just the chassis and engine serial numbers matching for legal purposes.

The big three had a habit of casting/stamping date codes into a lot of the components that would go onto a car. Date code information could be just the date of manufacture (anywhere from as generic as month/year to as specific as time of day/day/month/year/factory) to individually serial numbered items, such as engine blocks. There's a whole cottage industry of experts who have the experience to figure out what the date codes are, and to know what parts of what cars should have them.

The date codes are used to judge the potential originality of any given car. The chassis serial number, to the degree the original manufacturer made it so it would be difficult to alter, is considered the benchmark to which all other numbers are compared. So if the chassis number can be determined to have been built on a certain date, all other date-coded components are benchmarked against this date. The engine, if original to the car should have, to the degree assigned by the manufacturer, the same serial number as the chassis; if this was not how the manufacturer did it, then the date code on the engine should indicate that the engine was assembled prior to the assembly of the chassis. All other date codes of date coded components should show that the component was made before the chassis. Again, the experts will know how much time before is appropriate and how much is too much time before the chassis to be "authentic."

Muscle car collectors value original cars the highest because they are so rare. Imagine a typical muscle car that still has the distributor, water pump, radiator fan, that it came with when it left the factory. The next best thing is a numbers matching car, where the restorer went to the trouble of locating date coded, but often replaced, parts that "theoretically" could have come on the car the day it left the factory.

 

[Dan Sarandrea (Phila)]

It was the DMV fellow who explained to us how many number points were expected on the car, based on their massive vehicle database. Unlike the master mechanics/previous owners, at least he knew that the windshield VIN was missing. And he wasn't going thru menopause either....

Your car DID have the windshield serial number plate, see this screen cap from the WD episode lead-in.

As someone else said, maybe the WD crew folded it under during windshield repairs and neglected to fold it back into place?

 

[jimmyx]

If it really makes any difference to anyone, it's easy to check if your X is numbers matching. The data plate in the frunk (see 1st pic in post #2) is where the original "born with" engine number was recorded. This is true for the early cars (at least through '77) but I'm not sure if they did away with it on the later ones? As far as component date codes go, they aren't difficult to decipher if you look at them long enough. Most use 1-12 or A-L for the month and the last digit of the year. Some are just the numeric Julian date, and others also contain a one digit alpha/numeric that identifies a specific vehicle assembly plant. Some domestics have more intricate methods for foundry items like blocks and heads that pinpoint the actual production date and time (shift) that were helpful in tracking down internal manufacturing issues. The manufacturers coded parts for two reasons. The first was quality control (tracking time between failure rate or grouping batches that was sometimes necessary during product recalls) and the second was so the factory rep scrapping warranty parts could identify a potentially fraudulent warranty claim. GM (as did every other major producer) also used a simple coding scheme on repair orders to record the actual cost of parts in a way that a retail customer would be hard pressed to decipher:

G M P R O D U C T S
1 2 3 4 5 6 7 8 9 0

The retail price might have been $13.89 but the memo column might have shown DCR ($6.84). Done for the dealership accounting department in the days before computers. Lots of coded stuff in the auto industry, but much of it now relegated to the dustbin of history having been replaced with barcodes and other digital solutions. Up until the early '80s most factory reps were provided quite a library of 3-ring binders that showed every component date code scheme, hidden VIN locations, decoding of factory build sheets/punch cards, and how to decipher crayon inspection markings and printed inspection tags. Every year all State Police and DMV agencies in the country were provided the same information as well. Today, with the right software, they scan the barcode and more info than anyone needs to know is at their fingertips.

 

[tvmaster]

Your car DID have the windshield serial number plate, see this screen cap from the WD episode lead-in.

View attachment 55795

As someone else said, maybe the WD crew folded it under during windshield repairs and neglected to fold it back into place?

"I" said they folded it underneath. ME. lol. Nice pic though, that's how I found it was at one point there

 

[Dr.Jeff]

And he wasn't going thru menopause either....

Males also experience menopause.

In my rather extensive history dealing with the Calif DMV I've learned that you will get a completely different answer from every DMV employee you talk to, regardless of the question. And all of them will contradict what the official website or other records say. Furthermore ALL of it will be inaccurate.

 

[mlsceo]

Males also experience menopause.

In my rather extensive history dealing with the Calif DMV I've learned that you will get a completely different answer from every DMV employee you talk to, regardless of the question. And all of them will contradict what the official website or other records say. Furthermore ALL of it will be inaccurate.

True. True. And true.

 

[dllubin]

If it really makes any difference to anyone, it's easy to check if your X is numbers matching. The data plate in the frunk (see 1st pic in post #2) is where the original "born with" engine number was recorded. This is true for the early cars (at least through '77) but I'm not sure if they did away with it on the later ones? As far as component date codes go, they aren't difficult to decipher if you look at them long enough. Most use 1-12 or A-L for the month and the last digit of the year. Some are just the numeric Julian date, and others also contain a one digit alpha/numeric that identifies a specific vehicle assembly plant. Some domestics have more intricate methods for foundry items like blocks and heads that pinpoint the actual production date and time (shift) that were helpful in tracking down internal manufacturing issues. The manufacturers coded parts for two reasons. The first was quality control (tracking time between failure rate or grouping batches that was sometimes necessary during product recalls) and the second was so the factory rep scrapping warranty parts could identify a potentially fraudulent warranty claim. GM (as did every other major producer) also used a simple coding scheme on repair orders to record the actual cost of parts in a way that a retail customer would be hard pressed to decipher:

G M P R O D U C T S
1 2 3 4 5 6 7 8 9 0

The retail price might have been $13.89 but the memo column might have shown DCR ($6.84). Done for the dealership accounting department in the days before computers. Lots of coded stuff in the auto industry, but much of it now relegated to the dustbin of history having been replaced with barcodes and other digital solutions. Up until the early '80s most factory reps were provided quite a library of 3-ring binders that showed every component date code scheme, hidden VIN locations, decoding of factory build sheets/punch cards, and how to decipher crayon inspection markings and printed inspection tags. Every year all State Police and DMV agencies in the country were provided the same information as well. Today, with the right software, they scan the barcode and more info than anyone needs to know is at their fingertips.

My plate shows the engine type "128AS.040.4" but not the engine serial number.

 

[tvmaster]

Males also experience menopause.

In my rather extensive history dealing with the Calif DMV I've learned that you will get a completely different answer from every DMV employee you talk to, regardless of the question. And all of them will contradict what the official website or other records say. Furthermore ALL of it will be inaccurate.

Wasn’t in our case. He was spot-on.

 

[jimmyx]

My plate shows the engine type "128AS.040.4" but not the engine serial number.

It looks like the factory method of identifying production changes for replacement parts, much the same as the build date for the car is used. The engine family is "128AS". The second 3 digits I'm not sure about, but it seems that 040 is found on the '74's (yours and 3 others I checked). On my '75 & '77 it changes to 031. Would need to look at a wide variety of plates to see if there are other variations to make an educated guess at what it represents? The final digit is the year the engine was built. I checked my '74 and it is the same number as yours. My '75 final digit is 5, and my prior '77 is a 6, but the car had a late (Dec.) '76 build date.