I posted several weeks ago about a 1965 cpe with the L78 engine I looked at. I went back today and looked closely at the car and the documentation. This car definitely has a "961" two bolt main block. Additionally this car has a Bloomington Survivor award and all the original paperwork. No major component on this car appears to have been replaced and the engine and drivetrain appear to have never been out of the car. The car was purchased from Nickey Chevrolet. The Vin# is 15726. Any opinions on how this engine could have been installed in a corvette?
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Re: 1965 396 with 3855961 block
Rob,
I would say that several years ago when the original engine popped it's top it was a grease monkey that installed that block.
Later on someone stamped it trying to make a buck.
If it was a later serial number it would be an easier story to swallow. Not believable but easier to swallow and go on.
15,000 Nah!
Regards,
JR -
Re: 1965 396 with 3855961 block
Rob-----
While you've obviously ascertained, for sure, that the engine uses a '961' block, how do you know that it's a 2 bolt configuration? Are you just assuming that because conventional wisdom has it that all '961' blocks are 2 bolt or do you have other hard evidence that it's a 2 bolt?
I have it on good authority that there are documented cases of early 1965 Corvettes with L-78 using the '961' block. However, personally, I believe that these are '961' blocks which were manufactured with 4 bolt main configuration. As I mentioned before, while most '961' blocks may, indeed, have been manufactured with 2 bolt configuration, there's absolutely no reason why the Tonawanda engine plant could not have used the '961' block to build up 4 bolt main configuration engines. The main cap configuration has absolutely NOTHING to do with the block casting. The main caps are not even cast with the block. They are completely seperate castings. In fact, most of the big block 4 bolt main caps were not even cast at the Tonawanda foundry; they were cast at the old GM nodular iron foundry at Danville, IL. The use of a '961' casting for a 4 bolt main configuration finished block does require a little more machining than a '962' block. However, performing it would be "child's play" for the Tonawanda engine plant and the machining difference has more to do with tool longevity than anything else.
I feel very confident that the '961' block was originally used for some 1965 L-78 Corvettes. However, I'm equally confident that none of these were 2 bolt main configurations. The L-78 engine was ADVERTISED as a 4 bolt main engine; there's no way that GM would have produced any for sale that didn't meet this specification if only for that reason.In Appreciation of John HinckleyComment
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Re: 1965 396 with 3855961 block
Believe this is the same '65 several of us looked at in Denton, Texas for Al Grenning. All I can say is that when we looked at the '65 in Denton it looked very real. If replaced, it would have been a long time ago as the aging looked good. The other 2 fellows with me were very knowledgeable 65-67 big block folks and their consensus was that it could be the "real deal". Suggest you contact Al as he has some good info on 961 blocks in '65's. Gary.... #5895Comment
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Re: 1965 396 with 3855961 block
Joe
I have not gotten this car up on a lift yet, and have not been able to view the oil filter area for the telltale signs of a four bolt main. The documentation with this car includes an opinion from a knowledgeable individual that this is a "thin walled" 961 two bolt main block. If this is the case,how would this block find its ways onto the corvette assembly line?Comment
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Re: 1965 396 with 3855961 block
Gary, this car is the same one you are referring. Coincidentally, it was built on the same day as my 65 L78 cpe,April 21st. My car is Vin#15639.Comment
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Re: 1965 396 with 3855961 block
Rob-----
First of all, if it's a '961' block, it likely will be configured like a '961' block in the oil filter area. So, it may very well lack the "features" in this area which folks have come to expect will be found on 4 bolt main blocks. Those features are not necessarily part of a 4 bolt main engine. They certainly were not part of any expectation that any customer of the time would have had or, likely, cared about. So, whatever you find in the oil filter area will not really tell you what the main bearing cap configuration is. The only way to know that, for sure, is to remove the oil pan.
The term "thin wall" is a very relative term. The '961' block may well have been "thin wall" compared to a '962' block, but that's only because the '962' block had unusually thick cylinder walls. No one that bought a new 1965 Corvette with L-78 was promised or had any reason to expect that they would get a "thick wall" block or a '962' block. They were promised that they would get a 396 cid SHP engine. That's exactly what a '961' block could have been configured to give them.
Why would GM have used a '961' block instead of the usual '962' block for some L-78s? Well, I'm sure that it was some sort of production thing. In other words, for some reason there were not enough '962' castings available or produceable to meet the production requirement. Since a '961' block could be substituted with no real trouble, at all, that's what they did.In Appreciation of John HinckleyComment
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Re: 1965 396 with 3855961 block
Rob,
Is your 65 a 961 block or a 962? Seems to me that if there were production problems more than one 65 would have had a 961 block that day. Supply problems would not have been specific to serial number 15726.
If your Corvette is a 962 block, this casts more doubt on this 65 being an original 961 block.
Just trying to be logical and not wishing for something that cannot be proved.
Regards,
JRComment
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Re: 1965 396 with 3855961 block
Mine is a "962" four bolt main block.Comment
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Re: 1965 396 with 3855961 block
Joe I have been keeping numbers of 65 396 Corvettes for 26 years and have about 280 vin #s. I have 41 cars built before the 15726 car. I have never seen a real L78 with a 961 factory installed block. I would say it was a warranty replacement or a Nickey built car...Rob when you see the car check the cast date on the block and the rear end code....Joe there would be no reason for a 961 block to be at the St louis plant. I dont think they would have walked next door to the truck/Impala plant and grabbed ONE ,and if they did it wouldnt be an IF.....BillComment
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Re: 1965 396 with 3855961 block
Bill-----
It's my understanding that this car has an original appearing engine stamping. I don't know that, for sure, but that's my understanding. If it does, then that's further support for the fact that it's the originally installed engine. I seriously doubt that Nickey Chevrolet was going to do a "restamping" back in the mid 60's. It was a non-issue at that time, anyway. Since the engine also is reported to be an "original appearing" engine from the perspective of age, wear, etc., I don't think that it's a more recent "restamp", either. Plus, if it were a more recent restamp, I don't think that someone going to the trouble would have used an "incorrect" block to do it with.
If the engine has an incorrect deck stamping or a "restamped" deck, then it's obviously a non-original engine and all the discussion around it is completely academic and, in fact, meaningless.
My point is that there is NO reason that a '961' block could not have been built up into a 4 bolt main configuration by the Tonawanda engine plant. They were not TYPICALLY built-up to such a configuration, but there was NO fundamental reason that they couldn't be. As I mentioned earlier, the only thing required would have been a minor amount of machining difference and that really only relates to tooling longevity. Castings were designed to accomodate their final configuration with a minimum of machining necessary in order to minimize tooling wear and machining time. Using a '961' block for a 4 bolt configuration may have required a minor amount of additional machining, but that's all.
I do not suppose, at all, that the '961' block in question (or, any other) was "purloined" from the passenger car/truck plant. If it was used, it was built up at Tonawanda as a Corvette engine, coded "IF", and shipped to St. Louis Corvette.
The long-and-the-short of it is this: if the engine does not have an original stamping, then I don't even know why this whole subject regarding the '961' casting was even raised. If the stamping is a "forgery", then I don't understand how or why it would have been done by Nickey Chevrolet back in the 60s. If the stamping is original and the block is a '961', then I'd say that it HAS to be the original engine installed in the car. Even if it's the ONLY '961" ever installed in a 1965 Corvette. And, I don't think that it is.In Appreciation of John HinckleyComment
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And...
my 15778 L78 is a 962 block built in roughly the same timeframe!
Not only was the L78 advertized to have a 4-bolt main, it was also advertized to have a double journaled crank shaft that lower HP versions of the early BB didn't have.
But, if the car with the 961 block has gone through other hands/rebuilds these bits of forensic telltale are probably a mote point... On the judging field, I'd be hard pressed to deviate from the JG book and give the owner the 'benefit of the doubt' with this engine casting absent the owner providing 'documentation' to the contrary...Comment
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there was a E.S.L dated 5-18-65
"oil cooler installation,HD conversion part for 1965 396 RPO L-78" so i would have doubts that GM would supply a corvette block without the tapped holes for the remote oil cooler.Comment
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