L78 396/375 HP Long Block CKO Stamping
 

This is a L78 CKO stamped long block. The numbers are as follows: Block casting: 3999290 Dated E2471. Pad stamp: TO928CKO. Heads: 3964291 Dated E171(both).
This block is .040 over(actually .020 over its original 402 size) with no machine work required. There is a very nice sleeve in #5 that is virtually undetectable. The crank is very nice and does not need any machine work. The rods are 3/8" dimple with very nice Keith Black pistons. The heads look very good and have no porting or other mods. The pushrods and balancer are also included. I would install new bearings in this engine and run it. This engine spent most, if not all, of its life in a fresh water jet boat. The 71 date indicates that this engine was destined to be used as a warranty replacement in a Camaro or Nova L78 375HP and a manual trans. Perfect replacement for your non original engine L78. I can post pictures if anyone is interested. $3000.


Jason https://www.yenko.net/ubbthreads/imag...lins/beers.gif

Re: L78 396/375 HP Long Block CKO Stamping
 

https://www.yenko.net/ubbthreads/imag...-I-Have-It.gif

Re: L78 396/375 HP Long Block CKO Stamping
 

Nobody? OK, $2750. Otherwise I'll have to toss it in something https://www.yenko.net/ubbthreads/imag...lins/smile.gif.

Re: L78 396/375 HP Long Block CKO Stamping
 

You are saying/implying that this engine was assembled Sept 28,1971 using a 290 Block cast on May 24,1971. Alan Colvin says was this casting # was meant for 1972 240HP 402's.

Would somebody with more knowledge than I, please explain how this above engine received a 1970 CKO(L-78)deck code, for a NON 854 Block assembled more than a year after the LAST 1970 L-78 Camaro, Nova or Chevelle would have been built.

Just seeking education.......

Re: L78 396/375 HP Long Block CKO Stamping
 

Chuck, let me try to help...you are correct that the 854 block was used in the L78 in 70..it was also used in L34 motors(2 bolt). The 290 casting started sometime during 1971 and was made in both 2 bolt and 4 bolt. My 70 Fathom Blue L78 has a CE warranty motor dated E2572. They probably made these blocks long enough to satisfy any warranty or over the counter demands. The block is listed in the Mortec website for both 2 bolt and 4 bolt(70-72). I realize that the Colvin notes say that the only block to get 4 bolt mains in 71 was the LS-6 but I think that refers to assembly line installed units. These motors exist and are not that uncommon.

wilma

Re: L78 396/375 HP Long Block CKO Stamping
 

Tom, I agree with your comments......I just dont understand how or why a replacement engine assembled one year+ after the car run ended would still be stamped as a CKO and not as a CE ????
Also, isnt it unusual (but not impossible) for the block to not have been assembled/machined until four months after casting.
I have not seen near as many CKO/Big Blocks as you, but those I have inspected had cast/assy dates with in weeks.
Thanks for the ongoing L-78 education.........

Re: L78 396/375 HP Long Block CKO Stamping
 

Chuck, this is an interesting topic and deserves some further investigation. When you consider how many 396 cars were made in 70...there must be some reasoning behind the number of warranty motors or extras that were made for potential use. I would guess there are others on this site that may have more to contribute to the subject. I will review casting dates and assembly dates on some of my 70 cars to see how they stack up. Hopefully others will share their thoughts.

wilma

Re: L78 396/375 HP Long Block CKO Stamping
 

I will bring this subject to the 70 Camaro L-78 enthusiasts at www.nastyz28.com

Re: L78 396/375 HP Long Block CKO Stamping
 

Chuck, remember Nils in New Jersy who purchased an L78 Camaro back around Xmas? He had the original engine in it. The cast date was J 18 69 . The engine code stamped on the block was T0407CKO. This engine was final assembled 6 months after the block was cast. Now I am not saying I know why the 71 block has a CKO stamping, but I have seen some pretty scattered assembly dates, compared to casting dates. I figure that the L78 was still not a very common engine, there fore they cast a lot of blocks at one time, and used them as needed. Make sense? Just a guess on my part, but seems logical. Mike

Re: L78 396/375 HP Long Block CKO Stamping
 

My original 70 L78 Nova engine was cast A-28-70 and built April 24, I have seen another 70 L78 Nova block that was untouched and was cast early Feb 70 and built last day of April, these long spreads are definitely in existence.SULLY

Re: L78 396/375 HP Long Block CKO Stamping
 

Guys, I understand, acknowledge and agree with the examples you have given on 854 Casting dates and machining date spreads/differences...

However if I may repeat my question...........

Would somebody with more knowledge than I, please explain how this 290 casting which Colvin says wasnt introduced until the 1972 model year received a 1970 CKO(L-78)deck code???

Who has a real world example of a born with L-78 Chevrolet Model using a 290 Block casting ?????

Who has knowledge of any L-78 Camaro, Nova, Chevelle receiving a dealer replaced LIKE engine with ????? casting # block and ???? deck code (i.e. "CE")
Regards, <font color="purple"> </font>

Re: L78 396/375 HP Long Block CKO Stamping
 

Chuck, my 70 Fathom Blue L78 car has a dealer installed 290 4 bolt CE block. This car is an original L78 built 4th week of Feb. 1970. Dial chevrolet in Center Reach,NY(Long Island)did the replacement for the original owner in 1973. Don't know what else to say except these things are out there. I don't think you will find a 290 block that was factory installed as an L78.


wilma https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

Re: L78 396/375 HP Long Block CKO Stamping
 

Tom,

What Chuck is asking is how an engine produced in 1972 can receive a 1970 CKO code. i assume that your replacement block is NOT stamped with a CKO code.

Re: L78 396/375 HP Long Block CKO Stamping
 

[ QUOTE ]
Chuck, my 70 Fathom Blue L78 car has a dealer installed 290 4 bolt CE block.

wilma https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

[/ QUOTE ]

What is the replacement engine stamped?

Rick H.

Re: L78 396/375 HP Long Block CKO Stamping
 

Chuck,
No BB engine built after the 1970 model year was designated as an L78 unless it was used as a replacement engine. CKO was not used in 1971. Never used in 1972 as well.

Any engine used as a replacement was stamped CE. I would really question any 1972 replacement engine with a 1970 factory stamp.

Please post pictures of the stamp and casting numbers.

Rick H.

Re: L78 396/375 HP Long Block CKO Stamping
 

I have a theory: seem to recall reading somewhere that the hi-perf BB motors were a late cancellation for 71 model year. Maybe some blocks were produced and stamped in antcipation of being used and then relegated to warranty or service replacement. My engine satmp is CE360285 casting date is E2572.

wilma

Re: L78 396/375 HP Long Block CKO Stamping
 

I will post pictures of my stamps and date codes if it helps. Isn't there a bunch of 71 and 72 blocks running around with 70 LS6 stampimgs too?


Jason

Re: L78 396/375 HP Long Block CKO Stamping
 

My 69 Camaro SS has a 71 cast L-78 warranty block with it. It is stamped "CE1XXXX"

Rich

Re: L78 396/375 HP Long Block CKO Stamping
 

As we have seen any replacement block would be stamped "CE"

With this block being a late May 71 casting it could have been used in 1971 but with a September block stamp I think it was an attempt to be used in 1972 or restamped (nasty word) according to the original 1970 block stamp. https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Again, CKO was not used in 1971 or 1972 and any block correctly replaced under warranty would have been stamped with the replacement code.

Rick H.

Re: L78 396/375 HP Long Block CKO Stamping
 

Tirebird's LS6 T/A has a CRR code(?) and was one of the last crate motor LS6 available in '73-74.It had to come from Berger Chev. to L.A.

Re: L78 396/375 HP Long Block CKO Stamping
 

Rtck H, The "restamp/altered" subject is what I have been thinking.....but dont have the real world experience that others here apparently do have.....
Just asking that people that know the facts on these issues.......step up and tell us, like it is, like it was...

Re: L78 396/375 HP Long Block CKO Stamping
 

Pics of the engine stamping would go a long way to conclude this discussion. Anything available?

Re: L78 396/375 HP Long Block CKO Stamping
 

How about this?


Jason

Re: L78 396/375 HP Long Block CKO Stamping
 

Hmmm.... That came out funny. Let's try another picture.


Jason

Re: L78 396/375 HP Long Block CKO Stamping
 

OK, one more time! https://www.yenko.net/ubbthreads/imag...lins/smirk.gif

Re: L78 396/375 HP Long Block CKO Stamping
 

I'll be honest with you. It looks like someone went crazy with the stamping. You can see under the CKO stamp another stamping. Very faint but it's there. And what are the other stamps? Is that a GM replacement stamp? I've never seen one like that. Wait maybe I have. I'll think of it.

Are you sure that that is not an original marine engine?


Rick H.

Re: L78 396/375 HP Long Block CKO Stamping
 

Rick,

You come on a bit strong at times. It has never been stamped or decked before the CKO stamp. The broach marks are still present. The other stamps on the right of the pad are somewhat of a mystery. They read 2GME936. I thought they were from the machine shop that bored the engine but they could also be from the dealer that installed the block. For you to say "someone went crazy with the stamping" is a bit nieve. The "second stamping" you see is a shadow of the original stamping when the stamped bounced. This is a late 396 4 bolt main block with a CKO stamping. Like the late CRR LS6 engines, I imagine this was saved as a generic replacement for L78 engine. I may have also been a marine engine from day one, but the stamp on the pad was NOT added. I can take more pictures if anyone is interested.


Jason

Re: L78 396/375 HP Long Block CKO Stamping
 

Actually Jason I held back quite a bit about that block. The fact of the matter is this. NO CKO was used in 1971 or 1972. Any replacement motor replaced under warranty was stamped "CE" with a corresponding serial number.
You can speculate all you want but I'm not the one being naive.

Rick H.

Re: L78 396/375 HP Long Block CKO Stamping
 

I've had a gang of parts over the years from the General that you won't read about or find the casting numbers in any book.There's nothing wrong with those stampings,Jason.

Re: L78 396/375 HP Long Block CKO Stamping
 

If that is the case then someone should be able to produce another example just like Jason's. Anyone?

Rick H.

Re: L78 396/375 HP Long Block CKO Stamping
 

Look at Ratbirds CRR stamping. What about this being a 4 bolt main 290 block? hey are said to be 2 bolt only blocks but this is definitely a factory 4 bolt.


Jason


Jason

Re: L78 396/375 HP Long Block CKO Stamping
 

Will this help?
Mark Sheppard

Re: L78 396/375 HP Long Block CKO Stamping
 

Another picture

Re: L78 396/375 HP Long Block CKO Stamping
 

picture 3

Re: L78 396/375 HP Long Block CKO Stamping
 

picture 4

Re: L78 396/375 HP Long Block CKO Stamping
 

picture 5

Re: L78 396/375 HP Long Block CKO Stamping
 

[ QUOTE ]
Will this help?
Mark Sheppard

[/ QUOTE ]

Mark, what is the motor out of? Marine, truck, bus, etc.
Lets clear up this mystery.

Rick H.

Re: L78 396/375 HP Long Block CKO Stamping
 

Shoe leather tastes good https://www.yenko.net/ubbthreads/imag...mlins/grin.gif

Re: L78 396/375 HP Long Block CKO Stamping
 

A buddy in Fresno Ca. had this motor in storage for almost 20 years, I sold it for him about 3 years ago. The motor appeared to have been installed in both a boat and a vehicle at some points in its life. Wish I had more information. I sold it to a guy in Texas.
Mark Sheppard

Re: L78 396/375 HP Long Block CKO Stamping
 

[ QUOTE ]
Look at Ratbirds CRR stamping.



[/ QUOTE ]

Which Ratbird?

Also, I have seen the double stamp/ shadow stamp on other original non decked or restamped blocks.