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I assume if the block machining was not a success, then that one didn't count, they cast up another, and reattempted the machining.
Interesting, but I checked Berger, Nicky, Briggs catalogs, and so far Motion was the only one building up short blocks or partial engines, but will keep looking.
I was going to look for early articles on the White car (Otis), but I only had time to do one internet search on the prior Ownership.
I want to explore that car shipped to Europe, as I think I have the Vin correct.
I need to look up the Homologation also for the ZL-1 also.
I assume if the block machining was not a success, then that one didn't count, they cast up another, and reattempted the machining.
Interesting, but I checked Berger, Nicky, Briggs catalogs, and so far Motion was the only one building up short blocks or partial engines, but will keep looking.
I was going to look for early articles on the White car (Otis), but I only had time to do one internet search on the prior Ownership.
I want to explore that car shipped to Europe, as I think I have the Vin correct.
I need to look up the Homologation also for the ZL-1 also.
If the second production ZL-1 was shipped to Europe in 1970 that would certainly explain why the decades long search for it here never turned it up.
I assume if the block machining was not a success, then that one didn't count, they cast up another, and reattempted the machining.
Interesting, but I checked Berger, Nicky, Briggs catalogs, and so far Motion was the only one building up short blocks or partial engines, but will keep looking.
I was going to look for early articles on the White car (Otis), but I only had time to do one internet search on the prior Ownership.
I want to explore that car shipped to Europe, as I think I have the Vin correct.
I need to look up the Homologation also for the ZL-1 also.
I assume if the block machining was not a success, then that one didn't count, they cast up another, and reattempted the machining.
I think you are right, that they cast up another for every reject, to meet the order quantity, but the casting process would continue before they discovered rejects in castings or much later in machining.
The numbers are not stamped after casting, they are molded into the casting.
In the sand casting process, they have a "plug" that is shaped like the part they want to cast in metal.
So before they make the sand mold, they stamp the numbers on a piece of tape.
This tape is applied to the plug and then sand is packed around the plug.
It is a special refractory sand (green sand) that is made up of sand, bentonite clay and water as a binder. This sand sticks together almost like brick mortar.
Then the plug is removed and the sand mold is assembled from several sand mold segments, leaving a cavity and made ready for the foundry to cast the metal into the sand mold.
Once the metal is cast and cooled, the sand mold is destroyed and the part is vibrated to remove the sand from inside the block. What we call "Freeze Plugs" are really there to be able to get the sand out of the water passages......
Back to the tape...
On the last picture I posted, the date tape was stamped but the sequential number was not.
Just a blank piece of tape was applied. I am sure it was a good block, because it was offered for sale as a good OTC block. I doubt you will find any foundry rejects as they would have been remelted along with the flashing and runners...
If you look very carefully at the edges, you can see the tape used is rough around the edges.
It looks like some type of fabric reinforced tape. Something like "Duct Tape" and when the tape is torn off the roll, it leaves a rough edge imprinted into the sand.
The ones that are smooth were probably sand blasted or de-burred when they were removing the flashing from the bare casting.
Look at the edges of the tape on 353
We have other evidence of this on other castings...
You can see they applied a strip of this tape on the front of the block.
I am not sure if they used the tape to cover a defect in the plug, or if it was just a foundry worker messing around, but you can see a perfect impression of the tape they used for the casting and date numbers.
They may have added an additional casting at the end of the run for every reject, but the rejected blocks (along with their sequential casting #) was no doubt melted down and recast even before machining. I think it would be very confusing if they recast the same number of a rejected block with a later cast date. It is possible, but I don't think probable. I would think they would continue with the sequential numbering until the complete order quantity was filled.
But I hope at sometime in the future, we find documentation of an order quantity. Let's say for example if 400 blocks were ordered but they had 10% rejected from bad casting or machining. They would continue casting until the order quantity was fulfilled by casting up to number 440...
This is just a theory, but hopefully confirmation documents will be found.
Some of you guys are awesome. I have a number of these, but love that you loaded them in series.
Going first to the Darker 1968 L88, I think that was the car sitting on the other side of the 1968 with the ZL-1 in that one picture along the pit wall. The 1968 FIA Homologation car!!!!!!
Skipping to the light colored car (ZL-1), I wish the date stamps were clear to see. On the 1968 L88 there are some handwritten dates, which helps. I will pull mine up and see if dates are more visible. Back to the ZL-1, that I believe is the Car shipped to Europe to the french Greder and gang.
The Vin #194379s706401 built as per birthdate calculator 11/2/1968 (Yellow Racer entered for LeMans)
The Vin #194379s706753 built as per birthdate calculator 11/6/1968 (White T-Top Otis car)
Uhmmmmmm!
706401 Daytona Yellow
The back row shows this car and it's race paint jobs for the 24 Hrs of LeMans 1970-1975. First Driven by Greder, #2 1970 at LeMans. Sourced directly from Zora.
Zora got that ZL-1 engine #3 September 1968. Thus I think an initial batch was cast up and machined, and that would coincide with the earliest appearances of cars a short time later, and the one going thru the FIA Homologation process as an amendment.
Since you guys are awesome, I feel bad that I am falling behind on researching for interesting related topic. Thus they did testing, and come December 1968, they started making more blocks the second week of December 1968.
I will double check I have the correct Vin on that French racer. Let me try to run something I think I have on that car. I am not trying to be aloof, I just would hate to chase a lead, and find out I don't have the lead I thought I have.
Last edited by TCracingCA; 01-09-2024 at 12:24 PM.
Good point...
We are really just trying to verify Winter's cast numbers as well as their corresponding cast dates...Since these would be available in Camaros and OTC...
How many machined or rejected Winters, is a whole different can of worms...But are good points to note when considering what is out there..
Reynolds and Can-Am blocks... are more of a side note, as far as it relates to Corvettes...
But the subject of this thread ( The white car on Ebay) is kind of a mystery since he states it has the snowflake but no cast date....this engine is very interesting...
I do know one of the claimed ZL-1 Pace car'd one of the Can Am races in front of the McLaren's. I will try to run that down!
I only added Chaparral and McLaren history to show the ZL-1 won essentially two Can Am Championships (1968/69). They at least McLaren in 1970 switched to the Reynolds 390 Can Am Engines. I need to check what they put in the Chaparral 2J. And the ZL-1 did continue on with other teams.
In many of the Corvette Books, they start the ZL-1 history with the McLaren team, when Chaparral was the first.
Added some of this, just to help the history!
Last edited by TCracingCA; 01-09-2024 at 02:55 AM.
I think you are right, that they cast up another for every reject, to meet the order quantity, but the casting process would continue before they discovered rejects in castings or much later in machining.
The numbers are not stamped after casting, they are molded into the casting.
In the sand casting process, they have a "plug" that is shaped like the part they want to cast in metal.
So before they make the sand mold, they stamp the numbers on a piece of tape.
This tape is applied to the plug and then sand is packed around the plug.
It is a special refractory sand (green sand) that is made up of sand, bentonite clay and water as a binder. This sand sticks together almost like brick mortar.
Then the plug is removed and the sand mold is assembled from several sand mold segments, leaving a cavity and made ready for the foundry to cast the metal into the sand mold.
Once the metal is cast and cooled, the sand mold is destroyed and the part is vibrated to remove the sand from inside the block. What we call "Freeze Plugs" are really there to be able to get the sand out of the water passages......
Back to the tape...
On the last picture I posted, the date tape was stamped but the sequential number was not.
Just a blank piece of tape was applied. I am sure it was a good block, because it was offered for sale as a good OTC block. I doubt you will find any foundry rejects as they would have been remelted along with the flashing and runners...
If you look very carefully at the edges, you can see the tape used is rough around the edges.
It looks like some type of fabric reinforced tape. Something like "Duct Tape" and when the tape is torn off the roll, it leaves a rough edge imprinted into the sand.
The ones that are smooth were probably sand blasted or de-burred when they were removing the flashing from the bare casting.
Look at the edges of the tape on 353
We have other evidence of this on other castings...
You can see they applied a strip of this tape on the front of the block.
I am not sure if they used the tape to cover a defect in the plug, or if it was just a foundry worker messing around, but you can see a perfect impression of the tape they used for the casting and date numbers.
They may have added an additional casting at the end of the run for every reject, but the rejected blocks (along with their sequential casting #) was no doubt melted down and recast even before machining. I think it would be very confusing if they recast the same number of a rejected block with a later cast date. It is possible, but I don't think probable. I would think they would continue with the sequential numbering until the complete order quantity was filled.
But I hope at sometime in the future, we find documentation of an order quantity. Let's say for example if 400 blocks were ordered but they had 10% rejected from bad casting or machining. They would continue casting until the order quantity was fulfilled by casting up to number 440...
This is just a theory, but hopefully confirmation documents will be found.
Damn, you are on Corvette CIS Team #1--- Excellent, and thank you for the master class in how it happened. This is a Great Post!
TCracingCA—- Are you saying that the “brand new” 1969 ZL-1 sold to Greder by Duntov in June 1970 was actually #6401 built in November 1968 probably as an L88 prior to production ZL-1 vehicles?
TCracingCA—- Are you saying that the “brand new” 1969 ZL-1 sold to Greder by Duntov in June 1970 was actually #6401 built in November 1968 probably as an L88 prior to production ZL-1 vehicles?
Looks like it. we have up FIA submission and those led the next years entrants by about a year roughly. I bet they were planning on the LS-7, but that was delayed, then they extend the 1969 Production year out to December 1969. They wanted the latest, so Zora got them one of his test cars. Zora got enhine tha
The 1969 Greder car is alive and well in France, and I was able not only to see it, but sit in it briefly after meeting Henri Greder during the 2006 Le Mans Classic.
It is generally believed that this car was configured as an L88 when it first showed for the 1970 race in Yellow and after when the car was with Solar Productions while filming the movie Le Mans.
Henri Greder drove the yellow car, but I believe he purchased it from Solar productions for the 1971 and subsequent races.
While the car was certainly supported by Chevrolet, there are some things that make me doubt the amount of help that they did receive.
In this still from the movie the car clearly possesses correct FIA headlights and covers but the fender flares are not the correct GM part number flares offered with the L88 over the counter. Inteerestingly the car has never had the correct flares its entire life, though the ones on the car now are better looking than these. In the shot below the Kustom sidepipes appear plainly....
Today the car is a bit changed with more visually appealing "ZL-1" flares that appear to be the type originally sold by Ecklers 30 year ago. The vin on the car and the unbroken provenance of the car make it perhaps the most special of the C3 cars that went racing.
To my mind it is THE ONE to have. This is a 6 time Le Mans car, and one of the most unique and persistent race cars in the world... In this liverey and perhaps a couple prior ones 1972-75, I believe it ran a ZL-1.
Last edited by international blue; 01-10-2024 at 11:02 AM.
What a great racing history for #6401. Too bad it was not produced after #29219 which is credibly the first production ZL-1. The second is still unaccounted for. The story about Duntov’s involvement with it looks questionable when the flares are considered. By 1970, the L88/ZL-1 flares could be ordered by any US Chevy dealer parts dept, and were not even very expensive. I can’t believe that Duntov would have wanted Greder to use the ugly flares he was forced to cobble up without factory pieces. The factory pieces were just hand laid glass with white gel coat and a removable tab to hang on the upper fender to locate the flare. There were indents for screws to hold the flare on while the hang tabs were cut off and the flare was bonded to the fender and fared in. Besides looking good they were much simpler to install than the home made flares on the Greder car, as well as lighter.
3x2– That is a great set of pictures of a ZL-1 casting that must have been rejected but escaped the remelt. I have heard that the rejection rate of the castings were about 50%.
What a great racing history for #6401. Too bad it was not produced after #29219 which is credibly the first production ZL-1. The second is still unaccounted for. The story about Duntov’s involvement with it looks questionable when the flares are considered. By 1970, the L88/ZL-1 flares could be ordered by any US Chevy dealer parts dept, and were not even very expensive. I can’t believe that Duntov would have wanted Greder to use the ugly flares he was forced to cobble up without factory pieces. The factory pieces were just hand laid glass with white gel coat and a removable tab to hang on the upper fender to locate the flare. There were indents for screws to hold the flare on while the hang tabs were cut off and the flare was bonded to the fender and fared in. Besides looking good they were much simpler to install than the home made flares on the Greder car, as well as lighter.
3x2– That is a great set of pictures of a ZL-1 casting that must have been rejected but escaped the remelt. I have heard that the rejection rate of the castings were about 50%.
If I remember correctly, they tweaked the GM flares they installed, to fit their choice of rubber.
@3x2
Those are some awesome pictures!
Thanks for sharing!
I just wish they were higher resolution and showed the date / number...
I would love to own that block...Would make a great coffee table!...
But I don't know how this one got out of the factory???
It is hard to see, but I don't see any obvious defects, and it could be a good casting that was a stockpiled casting, just in case...
But on closer look...does that fuel pump boss cutout look funny? Maybe it was a defect casting? They didn't even cut the freeze plugs so there should still be sand in there!
I would really like to have more information about Winters...
It would be interesting to know their operating procedure in 1968-70ish...
We know they had a foundry. But did they have an in house machine shop also at that time? Was it in the same building / facility ? Or did they ship the cast blocks, manifolds and intakes to a third party machine shop? Warehousing of cast or machined pieces?.
It would be interesting to find these things out from someone who worked there at the time...
01-08-2024, 09:31 PM
