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Discussion Starter · #1 ·
A guy just told me that Tonawanda also made the heads, intake manifold and holley carb. Did the factory send these items to Atlanta or just the bare blocks ???? My 66 Chevelle SS 396 was built the last week of July 1966 but the block was cast in November 1965. the intake manifold ss dated July 1965, the heads are dated November 1965. Does this sound like its numbers matching or not ?????????????
Thanks,
Joe from Connecticut
 

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Joe I live 50 miles from the River road plant. I toured it in high school and did maintaince work there many times as A Ironworker. Tonawanda was A foundry and engine assembly plant. And still is a engine assembly plant. I dont recall see ing Holley carbs or any aluminum castings.
 

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I would say the engine is non matching. Usually the block/heads casting date is within a month of the build date on the car. 9 months.... I don't think so.
 

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They did have there own foundries pouring blocks, heads, cast iron intakes, and water pumps. Then they where machined and assembled and painted in-house at about 250 per hour. The cars manufacture plant installed the carb

the aluminum winters foundry was in New York as well.
 
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Discussion Starter · #5 ·
I would say the engine is non matching. Usually the block/heads casting date is within a month of the build date on the car. 9 months.... I don't think so.
Yo, my block is K 15 5 and the heads are K 26 5. Matching ???????????????
 

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that is July 9th
 

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The other dates are Nov of 65. Something is out of range here
 

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The casting dates would be considered matching to each other, but the assembly date is too far away to be matching. It is probably a restamp.

Is the block 3855961 or 3855962? A 360HP engine in a July 1966 car would not have a 962 block. And a 961 block cast in November of 1965 would most likely be installed in a 325HP engine.
 

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Discussion Starter · #12 ·
The casting dates would be considered matching to each other, but the assembly date is too far away to be matching. It is probably a restamp.

Is the block 3855961 or 3855962? A 360HP engine in a July 1966 car would not have a 962 block. And a 961 block cast in November of 1965 would most likely be installed in a 325HP engine.
You are quite wrong. A November 1965 stamp is for a 1966 and the block number 3855961 is both a 325 and 360HP block.
 

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You are quite wrong. A November 1965 stamp is for a 1966 and the block number 3855961 is both a 325 and 360HP block.
No the 962 was used up until dec jan for all 360hp. It wasn't until after they used the 961 block for 360.
 

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Discussion Starter · #15 ·
Post a picture of the stamp pad if you can. The casting and stamping dates seem pretty far apart so possibly a restamp.
black 66-9.jpg

No the 962 was used up until dec jan for all 360hp. It wasn't until after they used the 961 block for 360.
Dude, you are still wrong. The 962 block was for L78 only with some 360 engines used when the factory ran low on the 961's
 

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Tonowanda stopped using 962 blocks in 360HP engines in Jan/Feb and started using 2 bolt 961 blocks. Nov 65 961 blocks would likely have been used up by Feb, and long gone by July. Your picture of the Tonowanda stamp T0703EF is a restamp. Your engine is a likely Dec. 65 assembly that was restamped to appear original in your car.

Do you have photos of the block casting number and casting date?
 

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Bruce (AZCamino) is correct, that is obviously and unquestionably a restamped pad. All the fonts in the Tonawanda stamp are completely wrong. Whoever did it got pretty close on some of the Atlanta VIN stamp fonts, but the positioning of the A is obviously incorrect in comparison to several hundred known original 66 ATL stamnps.

To clarify the 961 vs 962 block comments above - In 1966 production --

- All 396/325 engines were 961 2-bolt blocks (it is possible there could be handful of 406 2-bolt blocks used very very very late in the model year).

- From the beginning of 66 production until December 10, 1965, all 396/360 engines were 962 4-bolt blocks. From December 11, 1965 through the end of 66 production, all 396/360 engines were 961 2-bolt blocks. There is a GM Engineering memo which states the exact date of the change over. (But again it is possible there could be handful of 406 2-bolt blocks used very very very late in the model year).

- From the beginning of 1966 L78 production (there is debate about when that actually started) until approximately mid May of 1966, all 396/375 engines were 962 4-bolt blocks. From that point through the end of 66 production, all 396/375 engines were 961 4-bolt blocks, except it is confirmed that there were a handful of 406 4-bolt blocks used very very very late in the model year.

But regardless, again, that is a restamped block in that photo.
 

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Jeff not to get of track when do you think the start of L78 production was? what is the latest 962 cast date you seen?
 

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Jeff,
The original poster says 193873 is the same as his VIN. Last car was 195611. If so his car could have been built in the last week of 1966 production at the Atlanta assembly plant. Is this late enough to have used a 406 block?
 

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Jeff not to get of track when do you think the start of L78 production was?
The earliest legitimate, "no questions" 66 L78 engine stamp I have ever seen is T0311EG. There is a T0310EG that might be real. That would jibe with the announcement in February of the availability of the option.

Everything I have ever seen earlier than that has had serious red flags attached, such as questionable broach marks, questionable stamps, fake paperwork, fake POPs, etc.

With that said, there is an engineering memo which suggests that management "re-approved" the option very shortly after 66 production started. But that info apparently never made it to Tonawanda until early December, 1965, which is what resulted in them stopping use of 962 blocks for L34 engines on Dec. 10. And that info never made it to dealers until February.

And notably, many of the March 66 L78 engines have blocks cast in mid and late December of 65. So Tonawanda kept casting 962 bocks (probably since they were told in early Dec. that there was going to be an L78 option available), but apparently those blocks sat around at Tonawanda for 3 months waiting for someone to actually order an L78, which would logically not have happened until dealers knew it could be ordered, which occurred in February.

With all that said, if someone had a dealer who would make enough calls and shake enough trees to find out the order code for an L78, maybe one got built before March. But if that happened, any proof of it (in the form of a car that does not set off lots of alarms for fakery) has not surfaced yet that I have ever seen.

what is the latest 962 cast date you seen?
Latest 962 casting date I have seen (and there are several of them with the same date) is D76. Latest 962 engine assembly date I have seen (and there are several of them with the same date) is T0509EG

Earliest 4-bolt 961 casting date I have seen (and there are several of them with the same date) is D226. Earliest 4-bolt 961 engine assembly date I have seen (and there are several of them with the same date) is T0513EG

Jeff,
The original poster says 193873 is the same as his VIN. Last car was 195611. If so his car could have been built in the last week of 1966 production at the Atlanta assembly plant. Is this late enough to have used a 406 block?
Yes. Earliest 406 casting date I have seen is F156. Earliest 406 engine assembly date I have seen is T0628EG. But even when use of 406's started, they continued to use 961's too, as there are plenty of 961 blocks with assembly dates after June 28 (including confirmed original 961 L78 engine stamped T0630EG).

*
On another note, what happened to the OP ?? I guess he did not like the news above about his deck stamp.
 
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