Great forum!
New guy here,
I've recently purchased a 70 Malibu Coupe and have been trying to decode the engine stampings.

The number cast near the bell housing is:
3970010
and the numbers stamped on the pad behind the altenator are: 10J251016 V1217CKT

I,ve referenced the bell housing number as a 350, but the stamped number has the CKT code.
Any insight would be great!
P.S. The second digit on the 10J251016 might be a "6", the rest are easily readable.

1972 CKT 350 tur hydramatic LT1 255hp 4bbl Z28
Is what one reference says.

The partial vin stamp for a 72 Camaro should be
12L(or N)+
The second digit is the year and 3rd is the assembly plant. J is Janesville which only car was Impala. Camaro was Los Angeles,Ca and Norwood, OH


Rene
66_Malibu

and its a 1970 engine, not a 1972

10J251016
1 - Chevrolet Division
0 - 1970
J - Janesville Wisconsin final assembly, only big Chevy cars and trucks came from Janesville
251016 - Last 6 digits of the cars VIN.

The suffix CKT has to be wrong. My bet is that is CNT, which is a 1970 350-300 HP with TH350 trans and police (both usage). Check it...

Goes to show 'ya what some of the 'references' are worth. That's why I qualified it with "one shows". The 10J looked suspicious to me too, but two web sources actually agree on the Camaro reference. They kind of 'feed' of each other........ sorry for the wrong info. graemlins/clonk.gif

have not heard back on weather the CKT was indeed wrong as I surmised?

Thanks all,

I've had a second and third look at the stamped # under the altenator and it's surely "CKT". One more number I finally managed to read is the date code on the rear of the block: K265

Casting Number = 3970010
Engine Vin = 16J251016 V1217CKT
Block Date Code = K265

At first I thought that second digit on the vin was a "0", but now I believe it's a "6", but that CKT stamps seems to reference the 72 camaro???

~Paul

If the second digit is truly a 6, then it is a 66 engine or a 76 engine and the J in the VIN derivative means it could not be a Camaro engine.

The plot thickens...

I've now found the intake casting number: 346248
and the date code on the heads (drivers side) is: L166

Hmmmm....? Does this animal appear to be from a 1976 something?

I've now determined the tranny is a TH350, but am unable to find any tags or stampings...
The engine has an HEI system. I've been doing web searches using the CKT engine suffix code.
If Janesville made Impala's exclusively, I've narrowed this engine down to a '76 or '77. Does anyone know of a database that lists Impala engines?

Thanks,
~Paul

10J251016
1 - Chevrolet Division
6 - 1976 model year engine
J - Janesville Wisconsin final assembly, only big Chevy cars and trucks came from Janesville
251016 - Last 6 digits of the cars VIN.


Its a 1976 engine, this proves it. End of the story. The CKT is questionable, it is not shown to be an engine code used in 1976. I checked all the GM parts books, interchange books and other code lists, CKT comes up as used on in 1970. So if yours is CKT, you appear to have the only one in existence?

Here is all the 350 codes used for passenger cars (big cars like Impala etc)
CMJ
CMH
CMM

Here are the 400 codes used
CTY
CTL
CSF
CTU
CTW
CTZ
CTL
CTM
CSJ


346248 I can't find but there is a 346249 being cast iron 4-bbl used on 305 and 350 engine with EGR. Don't' have the years used but it spanned many years and models.


L166
L - December
16 - day
6 - year cast

fyi
Janesville was and still is a GMAD plant (built other GM models too), in the 70's they built Full Size Chevy cars and trucks. Today they built the big SUV's, Suburban, Tahoe, Yukon, Yukon XL. They are also the ramp for all deliveries to the central states. For instance, my 2002 Firebird was built in St Therese, PQ, Canada, shipped by railroad to Janesville and by truck to dealer 400 miles North. TIT 9 days

MSA code book has a few more listed for 76 Impala 350 engine
CLF,CMN,CLH,CHS,CKU

Rene
66_Malibu

Thanks elcamino,
As luck would have it, GM builds one engine of it's kind and I get it in my Malibu! smile.gif ...not likely!

Thanks for checking the numbers out..., I appreciate you taking the time!! graemlins/beers.gif

Thanks to you too Shooter!

One last senerio came to mind(...arrghh!)
Could it be the '70 or '72 CKT 350 and the date codes on the block and heads are from 1965?

That would be a long time from casting to assembly though..., wouldn't it?

Maybe it's time to give it rest! ...the couriousity that is, ...not the engine! smile.gif

It ia a 1976 engine.
The casting number and casting date code tell that.
First, there were no 010 blocks in '66.
If it were an 86, it would have a one piece rear main seal.
The casting date of K265 translates to:
K=Nov
26=day
5=1975
So, the block was cast Nov 26, 75.
The engine code/assembly date, V1217CKT, gives us the date that the engine was machined and assembled. The 1217 translates to Dec 17. After the block was cast, it was assembled exactly 3wks later, which is just about right.
And, as mentioned, the second digit in the VIN (6) confirms it is a 76 engine.
As far as the CKT goes, it is VERY COMMON for engines to be stamped with codes which do not show up in ANY references. I don't know why, some just don't show up in any of the published literature, and frequently not even GM can locate the codes!
The 010 is one of the most common casting numbers used for the 4in bore small blocks. If first appeared in 69 and lasted until the very early 80s. The 010 block was used to make 302, 327, 350 engines. The 010 block was also built into both 2 and 4bolt versions. So, basically, what you have is a run of the mill '76 350 engine. THE ONLY WAY TO KNOW IF IT HAS 2 OR 4bolt MAINS IS TO PULL THE PAN.

Also, if it has the original '76 heads, throw them in the lake if you ever tear down the engine for a rebuild!!!!!
The LAST good PRODUCTION installed SB heads were on '74 model engines. In 1975, GM began to cut corners on SB heads. They were thinner, lighter castings. Many had 2 passages for the exhaust crossover--------------MORE HEAT, GREATER CHANCE FOR CRACKS TO DEVELOP!!! And, by 1977, PRODUCTION SB heads were thin junk. If you have a set of 75-later SB heads which are not cracked, they will be someday. I think you will discover that Billk will quickly confirm this.

Thank for the advice Tom...
It seems computer aided design left it's degenerative impact on automobiles right about the mid-70's era. :rolleyes: