1970 Casting Date vs Engine build date
Thread Starter
4th Gear
Joined: Apr 2018
Posts: 4
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1970 Casting Date vs Engine build date
I have a 1970 LS5 454 and am looking for a little help. The body build date is F01, June 1, 1970, Casting date K79, Nov. 7, 1969, 3963512 casting for big block. Engine is stamped T0525 CZU, I believe built May 25, 1970 at Tonnawanda. The NCRS does not allow a casting date and engine build date over 6 months apart. The national judges have looked at the stamping and did not believe the engine had been re-stamped. I don't have a build sheet and the burden of proof is on me to prove the engine is original. I have seen several instances of this for 1970 cars and maybe someone on this forum is in the same boat. Seems to me if the stamping is good and the casting date is prior to stamping, it would have to be the original engine. Any help would be much appreciated.
Team Owner
Joined: Sep 2006
Posts: 31,160
Likes: 4,236
From: Westminster Maryland
Hi md01,
Welcome!
First post!
At which National Convention was your car Flight Judged.... how recently?
What are the dates like on other dated engine components .....heads, intake, exhaust manifolds, etc. Are they typical for an engine assembled near the end of May?
Any chance of seeing a photo of the pad?
Regards,
Alan
Welcome!
First post!
At which National Convention was your car Flight Judged.... how recently?
What are the dates like on other dated engine components .....heads, intake, exhaust manifolds, etc. Are they typical for an engine assembled near the end of May?
Any chance of seeing a photo of the pad?
Regards,
Alan
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
You may try contacting Al Grenning. From what I hear he has an extensive library of photos of stamp pads. He may be able to look over what you have, give an informed opinion whether it's original or been tampered with. Sounds like the date code fell just outside the 6 month rule.
Here's his web site address.
http://ccas4vettes.com/
Here's his web site address.
http://ccas4vettes.com/
Advanced
Joined: Apr 2008
Posts: 60
Likes: 25
From: Roscoe IL
We have seen a few of these. We (NCRS Judging) had one at the Laughlin, NV Regional meet last year and another at the Altoona Regional last August. Terry McManmon has I think two on his list. So... If your's is real, this would make number five or six?
I have collected the VIN numbers, build dates, engine build dates and casting dates from those cars. If you would care to share those with me, I would appreciate it. I'll add it to my the list.
When the 70-72 TIM&JG is updated again, I plan to add this to the Manual. I know the normal Mechanical judges are aware of it and Chuck Berge is aware of it. As we get older, we sometimes need help remembering though :-)
I have heard several stories why this happened, block being returned from school, advertising, promotions, etc. Gm would use them, as they were still good.
Gary Bosselman
I have collected the VIN numbers, build dates, engine build dates and casting dates from those cars. If you would care to share those with me, I would appreciate it. I'll add it to my the list.
When the 70-72 TIM&JG is updated again, I plan to add this to the Manual. I know the normal Mechanical judges are aware of it and Chuck Berge is aware of it. As we get older, we sometimes need help remembering though :-)
I have heard several stories why this happened, block being returned from school, advertising, promotions, etc. Gm would use them, as they were still good.
Gary Bosselman
Team Owner
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From: Massillon,Ohio USA
2020 C3 of the Year Finalist - Unmodified
Cruise-In VI Veteran
St. Jude Donor '08-'09-'10-'11-'12
About 12-14 years ago a friend of mine had a very nice original '71 LS-5 automatic car that was built Dec 7, 1970 and that car's block was cast around April 6, '70 assembled on April 25. I'm no pad expert, but have looked at hundreds of them and I believe 100% it was original to the car. The car even got Bloomington Gold Survivor and the judges then too believed the block was original to the car. I think Terry Mc. was one of the Survivor judges too that said he believed it was the original engine. Not sure, but wasn't there a strike either at the engine plant or the Corvette assembly plant around that time? What's ironic is we were at an NCRS Chapter meet in Pittsburgh, PA around that same time and there was an owner there who had a Silver '71 LS-5 coupe that had a VIN# super close to my friend's car and it too had like an 8 month time frame between the block casting date and build date of the car.
Last edited by Paul Borowski; Apr 22, 2018 at 09:23 PM.
Drifting
Joined: Aug 1999
Posts: 1,451
Likes: 84
From: Round Rock TX
My 70 LS5 is a build date on Trim Tag G18. The block looks like C260 (hard to read first character), heads E10 and D10, don’t recall intake. The stamp shows T0705CZU. I have the tank sticker as well.
Melting Slicks
Joined: Feb 2017
Posts: 2,377
Likes: 838
From: New York
2017 C3 of the Year Finalist
St. Jude Donor '20- '21
See MoonDog01, interesting not bad for a second post. I hope this all works out for you and we all learn a little about how exactly these cars were built. I doubt GM would waste anything that was functional and had value.
Hell think about it what happened to the engine they used for the brochure after the photo shoot, destroyed, not likely. Put back in line months later to be placed into a Vette.
Great stuff, very interesting. Ike
Hell think about it what happened to the engine they used for the brochure after the photo shoot, destroyed, not likely. Put back in line months later to be placed into a Vette.
Great stuff, very interesting. Ike
Thread Starter
4th Gear
Joined: Apr 2018
Posts: 4
Likes: 0
We have seen a few of these. We (NCRS Judging) had one at the Laughlin, NV Regional meet last year and another at the Altoona Regional last August. Terry McManmon has I think two on his list. So... If your's is real, this would make number five or six?
I have collected the VIN numbers, build dates, engine build dates and casting dates from those cars. If you would care to share those with me, I would appreciate it. I'll add it to my the list.
When the 70-72 TIM&JG is updated again, I plan to add this to the Manual. I know the normal Mechanical judges are aware of it and Chuck Berge is aware of it. As we get older, we sometimes need help remembering though :-)
I have heard several stories why this happened, block being returned from school, advertising, promotions, etc. Gm would use them, as they were still good.
Gary Bosselman
I have collected the VIN numbers, build dates, engine build dates and casting dates from those cars. If you would care to share those with me, I would appreciate it. I'll add it to my the list.
When the 70-72 TIM&JG is updated again, I plan to add this to the Manual. I know the normal Mechanical judges are aware of it and Chuck Berge is aware of it. As we get older, we sometimes need help remembering though :-)
I have heard several stories why this happened, block being returned from school, advertising, promotions, etc. Gm would use them, as they were still good.
Gary Bosselman
Thanks, Mitch
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Thread Starter
4th Gear
Joined: Apr 2018
Posts: 4
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Hi md01,
Welcome!
First post!
At which National Convention was your car Flight Judged.... how recently?
What are the dates like on other dated engine components .....heads, intake, exhaust manifolds, etc. Are they typical for an engine assembled near the end of May?
Any chance of seeing a photo of the pad?
Regards,
Alan
Welcome!
First post!
At which National Convention was your car Flight Judged.... how recently?
What are the dates like on other dated engine components .....heads, intake, exhaust manifolds, etc. Are they typical for an engine assembled near the end of May?
Any chance of seeing a photo of the pad?
Regards,
Alan
Safety Car
Joined: Sep 2007
Posts: 4,451
Likes: 326
From: Indy Indiana
you just don't know the factory first in first out system and how well it was maintained. some blocks failed initial test and then went into a fix area for months, some blocks failed under warrantee and were sent back to the factory for refurbish, some blocks might sit built in the assembly factory for months awaiting a car due to strikes, some blocks might sit at the factory before and after being built.
in general if the process worked correctly and the line moved, and the trucks delivered the parts, then the 6 month rule is gospel. but there were many exceptions.
factory fonts, broach marks and correct patina factor in to what is correct. and engine originality is nothing but a plus or minus degree of faith when things can't be proven.
you just hope your appraiser, your judge, or your buyer can be convinced.
in general if the process worked correctly and the line moved, and the trucks delivered the parts, then the 6 month rule is gospel. but there were many exceptions.
factory fonts, broach marks and correct patina factor in to what is correct. and engine originality is nothing but a plus or minus degree of faith when things can't be proven.
you just hope your appraiser, your judge, or your buyer can be convinced.
Melting Slicks
Joined: Feb 2017
Posts: 2,377
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From: New York
2017 C3 of the Year Finalist
St. Jude Donor '20- '21
Joewill, In a engine that failed under warranty and was replaced. What happened to the original, returned to GM and repaired? Then what? Back in the assembly line? I hope not!!!
Ike
Ike
Safety Car
Joined: Sep 2007
Posts: 4,451
Likes: 326
From: Indy Indiana
maybe, maybe not... you never know what the bean counters do and say about policy 48 years ago to save a buck...
the ncrs judging manual states that failed engine assembly parts that are salvageable are returned to the line from the heavy repair area, then are reconfigured and this caused time spans to exceed the norm..
the ncrs judging manual states that failed engine assembly parts that are salvageable are returned to the line from the heavy repair area, then are reconfigured and this caused time spans to exceed the norm..
Safety Car
Joined: Sep 2007
Posts: 4,451
Likes: 326
From: Indy Indiana
If I was a buyer, the lack of 48 year old patina would certainly raise a big flag for me on this stamp, even though the fonts and placing of the characters stamp look correct.. I would need a much better foto to determine the broach marks, which are hard to see on this example.
Advanced
Joined: Apr 2008
Posts: 60
Likes: 25
From: Roscoe IL
Mitch,
Bring the car to Las Vegas. I'll be there with my 72 for Bowtie judging. It was approved in Greenville a week ago.
I probably can predict who will be judging Mechanical in the 70-72 group. I probably won't be judging, but after Altoona last year, I am pretty sure they won't make the same mistake "we" made in Laughlin. We have seen too many examples since then.
Hope to see you there.
Gary Bosselman
Bring the car to Las Vegas. I'll be there with my 72 for Bowtie judging. It was approved in Greenville a week ago.
I probably can predict who will be judging Mechanical in the 70-72 group. I probably won't be judging, but after Altoona last year, I am pretty sure they won't make the same mistake "we" made in Laughlin. We have seen too many examples since then.
Hope to see you there.
Gary Bosselman
Team Owner
Joined: Sep 2006
Posts: 31,160
Likes: 4,236
From: Westminster Maryland
Hi jr,
"What is that 0 3 0 stamped on the pad ?"
I'm thinking the stamps indicate that the shop that rebuilt the engine at some time bored the cylinders .030".
Regards,
Alan
"What is that 0 3 0 stamped on the pad ?"
I'm thinking the stamps indicate that the shop that rebuilt the engine at some time bored the cylinders .030".
Regards,
Alan
Last edited by Alan 71; Apr 24, 2018 at 02:03 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
This kind of cr@p is why I am not an NCRS member. I applaud their "charter"; but the actions taken sometimes make little sense.
If I have built a 'clone' car from all aftermarket parts, but make them LOOK exactly like the real thing, NCRS will give me a nice award. But, if I bring in an authentic, all-original car that some finicky judge says has a "questionable" date code because of some NCRS-created rule about a "6-month window", he might send me home packin'.
It's absurd to allow EITHER of those situations to occur. But, that's how they've set it up. I doubt that more than a few NCRS judges even know what a broach looks like... nor how it operates... nor how the surface finish of the pad CHANGES appearance based on how recently the bar has been sharpened. And yet, they can question a legitimate car for some minor difference in THEIR date assumptions. Goofy...
P.S. Just for grins... This is an OPEN forum. You bring up NCRS-specific stuff and folks have the right to comment on such posts in positive or negative fashion. If you want to ONLY talk with NCRS folks, go to the NCRS site.
If I have built a 'clone' car from all aftermarket parts, but make them LOOK exactly like the real thing, NCRS will give me a nice award. But, if I bring in an authentic, all-original car that some finicky judge says has a "questionable" date code because of some NCRS-created rule about a "6-month window", he might send me home packin'.
It's absurd to allow EITHER of those situations to occur. But, that's how they've set it up. I doubt that more than a few NCRS judges even know what a broach looks like... nor how it operates... nor how the surface finish of the pad CHANGES appearance based on how recently the bar has been sharpened. And yet, they can question a legitimate car for some minor difference in THEIR date assumptions. Goofy...
P.S. Just for grins... This is an OPEN forum. You bring up NCRS-specific stuff and folks have the right to comment on such posts in positive or negative fashion. If you want to ONLY talk with NCRS folks, go to the NCRS site.
Last edited by 7T1vette; Apr 24, 2018 at 11:25 AM.