#21  
Old 09-25-2021, 11:15 PM
tom s tom s is offline
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Did all blocks get a EUN?I have a 70 engineering block with 303 stamped on it.Will have to look again as I remember it has no vin or EUN.914 4 bolt block.Built as a 428 in my 69 bird.Tom

  #22  
Old 09-26-2021, 02:22 PM
jhnichols2 jhnichols2 is offline
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I haven't cleaned the TA up enough yet to get the Tanny / axle dates yet. A project that has been sitting for a while until my 67 GTO gets done.

  #23  
Old 09-26-2021, 05:19 PM
SD455DJ SD455DJ is offline
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Quote:
Originally Posted by SD455DJ View Post
My '70 Formula is a 04D Norwood build car. Here are the date codes on it:

Block - D060
Heads - D100/D140
Int. Man. - C100
Exhaust Man. - D080/D080
Carb - 0570
Dist - 9G3
Alt - 0B23

I hope this helps! It looks like dates are all over the place!

Dennis
Here's the EUN of the above engine. It also has a double strike of the VIN stamp.

Dennis
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  #24  
Old 09-26-2021, 08:42 PM
John V. John V. is offline
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Quote:
Originally Posted by 72projectbird View Post
My 3rd week of March 70 has its original engine, which was built in January of 70.
Not to pick on 72projectbird's response but to use it to illustrate an important (in my view) point.

Engine blocks have cast date tags. These tags represent the date that the block was cast.

It does NOT represent when the Engine was assembled in Pontiac's one and only engine plant located at the Pontiac, Mich home plant. One should NOT use the block cast date to indicate when an engine was "built".

The EUN can be used to establish the approximate date that the engine was assembled.

Perhaps it can be done more easily but I have spent years collecting '64 engine data (when partial VINs were not yet added to the block at final assembly as a theft deterrent and the year Pontiac quit stamping the full VIN as they had for some years through the '63 Model Year). From the data I can generally figure out the expected cast date and EUN based on the Time Built code on the Data Plate. I've been able to establish a decent correlation between EUN, block cast date, and Time Built code for '64 Pontiacs. And there are always anomalies that fall outside the expected ranges. Only thing certain, the block used in the original engine was cast before the car shipped.

What I have noticed over the years, these general correlations seemed to hold up pretty well throughout the '60s.

But starting with the 1970 Model Year, the correlations have seemed to be far less predictable.

I don't know if I've ever discussed Norwood's '70 engine. My knee-jerk reaction, I'd be curious to know if his EUN shows an engine assembled many months before his July TA was final assembled or if the EUN shows a late assembled engine assembly that happened to make use of a much earlier cast block.

I have encountered rare examples of both scenarios from the mid '60s. Neither scenario would surprise me and perhaps both scenarios were more commonplace beginning in '70.

The stamping of the partial VIN on the block adds another data point for '68 up engine assemblies which can be helpful in detecting restamps and other mods that attempt to disguise a NOM as original.

I wrote the above but forgot to post it yesterday. And now I see Norwood has posted his EUN.

Without benefit of significant data, it looks to me that his EUN was assembled around early Feb. If this was a '64 engine assembly, it would be unusual (but far from impossible) for the block to have been cast 2 months before it was assembled into a complete engine assembly. And also unusual for the completed engine assembly to have sat in Final Plant inventory after arriving at the Assembly Plant for some 5 months before being installed into a car build.

The latter, IMO, did occur more often at the end of Model Year production precisely because the Plant tended to operate somewhat on a First In, Last Out inventory control. That is, engine assemblies arrived in "bulk" and were placed into some form of inventory. As they were being used up in production, the next batch of engine assemblies arrived, burying whatever inventory remained.

At Model Year build out, inventories of everything (in particular, components that would not be carried over to the new Model Year) would be drawn down.

At that point (typically July being the end of MY production), engine assemblies that had long been buried at the back of the storage location collecting dust got uncovered and pulled for a build.

All speculation, but that would be my explanation for how this Feb assembled engine assembly became original to a 7C build at Norwood.

A similar explanation could be used for why a mid Dec '69 cast block wasn't made part of an engine assembly until Feb '70 based on how block castings may have been stored at Pontiac, Mich either prior to machining or engine assembly after machining.

As I mentioned, such disparities were never unknown but they do seem to have become more common after the '69 MY just by anecdotal evidence that I've come across thru the years.

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  #25  
Old 09-26-2021, 09:26 PM
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Thanks for your post John.



Here's a link to my EUN Search page
Put 1970 into the Year input then hit submit.

Would Pontiac have sent Norwood and Van Nuys engine assemblies prior to the Feb release of the Firebird? Would they have the EUN's on them and when is VIN stamped? Just before going to the body line?

The RA III and RA IV seem to be scattered more than the plain jane engines and the other vehicles like A-body, G-body, and B-body are a little bit organized.


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  #26  
Old 09-27-2021, 10:35 AM
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72projectbird 72projectbird is offline
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Quote:
Originally Posted by John V. View Post
Not to pick on 72projectbird's response but to use it to illustrate an important (in my view) point.

Engine blocks have cast date tags. These tags represent the date that the block was cast.

It does NOT represent when the Engine was assembled in Pontiac's one and only engine plant located at the Pontiac, Mich home plant. One should NOT use the block cast date to indicate when an engine was "built".

The EUN can be used to establish the approximate date that the engine was assembled.

Perhaps it can be done more easily but I have spent years collecting '64 engine data (when partial VINs were not yet added to the block at final assembly as a theft deterrent and the year Pontiac quit stamping the full VIN as they had for some years through the '63 Model Year). From the data I can generally figure out the expected cast date and EUN based on the Time Built code on the Data Plate. I've been able to establish a decent correlation between EUN, block cast date, and Time Built code for '64 Pontiacs. And there are always anomalies that fall outside the expected ranges. Only thing certain, the block used in the original engine was cast before the car shipped.

What I have noticed over the years, these general correlations seemed to hold up pretty well throughout the '60s.

But starting with the 1970 Model Year, the correlations have seemed to be far less predictable.

I don't know if I've ever discussed Norwood's '70 engine. My knee-jerk reaction, I'd be curious to know if his EUN shows an engine assembled many months before his July TA was final assembled or if the EUN shows a late assembled engine assembly that happened to make use of a much earlier cast block.

I have encountered rare examples of both scenarios from the mid '60s. Neither scenario would surprise me and perhaps both scenarios were more commonplace beginning in '70.

The stamping of the partial VIN on the block adds another data point for '68 up engine assemblies which can be helpful in detecting restamps and other mods that attempt to disguise a NOM as original.

I wrote the above but forgot to post it yesterday. And now I see Norwood has posted his EUN.

Without benefit of significant data, it looks to me that his EUN was assembled around early Feb. If this was a '64 engine assembly, it would be unusual (but far from impossible) for the block to have been cast 2 months before it was assembled into a complete engine assembly. And also unusual for the completed engine assembly to have sat in Final Plant inventory after arriving at the Assembly Plant for some 5 months before being installed into a car build.

The latter, IMO, did occur more often at the end of Model Year production precisely because the Plant tended to operate somewhat on a First In, Last Out inventory control. That is, engine assemblies arrived in "bulk" and were placed into some form of inventory. As they were being used up in production, the next batch of engine assemblies arrived, burying whatever inventory remained.

At Model Year build out, inventories of everything (in particular, components that would not be carried over to the new Model Year) would be drawn down.

At that point (typically July being the end of MY production), engine assemblies that had long been buried at the back of the storage location collecting dust got uncovered and pulled for a build.

All speculation, but that would be my explanation for how this Feb assembled engine assembly became original to a 7C build at Norwood.

A similar explanation could be used for why a mid Dec '69 cast block wasn't made part of an engine assembly until Feb '70 based on how block castings may have been stored at Pontiac, Mich either prior to machining or engine assembly after machining.

As I mentioned, such disparities were never unknown but they do seem to have become more common after the '69 MY just by anecdotal evidence that I've come across thru the years.

Jeez, I guess I should've said cast, not built.

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  #27  
Old 09-27-2021, 01:15 PM
DANTIP DANTIP is offline
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Default RAIII dates

I have a RAIII (Norwood car) J099 cast 979914 block with an EUN of 0402790 for a car shipped on 05-08-70.
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  #28  
Old 09-29-2021, 01:20 PM
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fiedlerh fiedlerh is offline
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Obviously the Pontiac plant had to build engines in advance of anticipated sales. It is possible that sales of Ram Air varieties were not as high as the factory had anticipated. I remember back in the day Ram Air varieties were virtually unheard of until the Judge came out. Many dealers pushed daily drivers over performance.
It makes sense from a production standpoint to build similar engines in batches. Bread-and-butter engines like the 350/2bbl were probably a regular production item; build them and ship them. A batch of low-volume high-performance engines might take months to use up, hence long times between casting dates and EUNs. The factory HAD to have engines available or risk delaying orders.

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  #29  
Old 09-30-2021, 11:21 AM
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unruhjonny unruhjonny is offline
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Quote:
Originally Posted by fiedlerh View Post
...
It makes sense from a production standpoint to build similar engines in batches. Bread-and-butter engines like the 350/2bbl were probably a regular production item; build them and ship them. A batch of low-volume high-performance engines might take months to use up, hence long times between casting dates and EUNs. The factory HAD to have engines available or risk delaying orders.
I have understood up to this point, that this is precisely why a date spread on a YS cannot be in any way compared to a YZ ect;
The YS was a 'bread and butter' 400-4bbl used in many lines, and several plants, while the YZ was exclusive to the GTO & Firebird.

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  #30  
Old 09-30-2021, 01:10 PM
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Formulabruce Formulabruce is offline
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From my research, and some first hand info from relatives,
I have a couple thoughts.
1. In the '70 model year there were at least 5 .....400 cuin. Engines Built by Pontiac. SAME BLOCK casting.
2. Lots of #12 and #13 heads were readily available. And show up close to the block dates in most cases.
3. Intakes, plentiful and a ton built in Oct, Nov for the 70 model year, shared with the 455 as well, show up pretty close to blocks casting.
4. This leaves the "D" Port RA Exaust manifolds.
This is where I know there was supply issues. Dates on Originals have been real close to assy, and far from block casting in many cases.
If there were plenty, the 455HO Would have got them on the GTO more than likely.
So I attribute many, NOT ALL, date " oddities" on RA engines to Exhaust manifold availability.
Some blocks were " Training Blocks" as well as poor casting blocks. Lots of waste.
Most all 350's ( same crank) and 400's of 70 that are Not RA SEEM to be closer in dates across the cast dated components.
In the late 70's we had big delays in getting these same manifolds due to cracking and leaks demand, and some OTC demand.

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  #31  
Old 10-03-2021, 02:41 PM
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This might be of some interest:
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