Thread: SBC Identification Numbers Decifer Help

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robot i didnt mean to imply that worth more meant top dollar, this isnt some DZ motor were talking about, but from a restorer standpoint, if you can matchup a 68' motor application to the correct car it certainly helps overall value of the vehicle, id hate to go dropping it into a car just to sell when there are plenty of people that could use the motor much more than what my purpose is for. heck id even trade em this one for a project that met their needs for another runner with the later accessory holes for the power steering mounts on the heads. but i know what you mean about scrapin stuff out or melt downs, ive done enough business with vintage motors to know that someone is always looking for a specific year range or model to at least offer it up before i proceed on a motor swap.

One of these sites should help you find the info,

Chevymania!
Chevy Small Block Cylinder Head Codes - Chevy Camaro
E-ROD LS3 | Hot Rod with Crate Engine | GM Performance Parts
http://www.mortec.com/sfampage.htm

OSK....the 64 fitment is for an Impala with the "C" code. 195hp 3 speed tranny and a 2 bbl

Bad80 I've checked all those. The thing is the c code doesn't match the cast number cause the cast number wasn't used until 1968. I'm guessing its possible the suffix area is either worn off and or that second digit on the partial vin is an 8. Cause the way its stamped looks more like 68/69 format than later models and the early 60's . Any thoughts from the pics?

Hi Mike,I have been following along this thread and as I too have not been able to make out what sort on engine I have in my Bucket. I purchased the car as a 327 cu. in. and when I looked into the numbers etc. I came up with 350 cu.in. . But reading this site I honestly don't know anymore. The thing is that the engine is such a strong runner,apart from changing the intake and other dress up items,I have had no need to pull it apart. So I have taken some photos of the markings and if you can,I would appreciate your verdict please.Thanks for your trouble,Whip.Messy Garage 010.jpgMessy Garage 006.jpgMessy Garage 007.jpgMessy Garage 009.jpgMessy Garage 011.jpgMessy Garage 010.jpgMessy Garage 006.jpgMessy Garage 007.jpgMessy Garage 009.jpgMessy Garage 011.jpg

CKJ code was used in three applications:
1973 Chevelle 350 ci 175 hp turbo 400 L-48 4bbl VIN K
1977 Chevelle 350 ci 170 hp turbo 350 LM-1 4bbl VIN L
1973 IMPALA 350 ci 175 hp turbo 400 L-48 4bbl VIN K

mike in tucson

engineident.jpg

Im focused on the circled numbers in the pic since they are fairly worn, the suffix code could have more that came after the letter C so id like to start with just the vin id number and work from there, robot, you've been a big help in checking these things so far so id like your opinion on the numbers cast here if you could. im about 99% positive the number 4 is correct even though its pretty worn out, but the second digit could be either S,6, or 8. as far as the suffix letter goes?? well it could have more but theres nothing on the front plate thats left of it that gives me any incling that there are letters or numbers following it. The things we know for certain is the motor cast number is found on only 1968 327's, 1969-1979 350's and 68' 69' 302's, given the suffix does not resemble a DZ code i can rule out the 302's easily, we know the heads are 68' heads either from a 307 or 327 but those could have been swapped easily over the lifetime of the motor itself, this motor does not have the road draft tube so it would have to be a later 60's small block and up since it was mandated that the PCV valve replaced the road draft tube like earlier ones, i know that from my 63-65 cast 327 in researching that motor in the last few years. so putting this as a 57' 283 i would seriously doubt due to the lack of a draft tube on the motor.

Thanks Mike for that,now I know for sure. The young guy I brought it off told me it was a 327 and TH350 and as it was such an excellent buy at $5000.00 it was mine. When I stripped it down for the rebuild the trans turned out to be a TH400 so I'm still pleased with the overall package.

I enlarged the pic 4X what you have posted....the number is
16B467145 because there is a good 6, a good 4, and a good 1
to compare the light stamped digits with. The only marginal call
is the B at the third place.... could this block have been decked
in past life? You might do a bit of research regarding late model
VINs.....this is either the complete VIN or a derivative of a 17 digit VIN

However, the 16B prefix is not a typical GM 9 digit VIN series.....
Sometimes, a block is rebuilt and some stuff is stamped....but 9
digits seems extremely long for a rebuilder.

I've been doing alot of research into the VIN format for chevy small blocks pre-70's, according to what i have found the format on this motor is consistant with the same format used in 68' 16847145, 1-Chevy 68-Production Year followed by the production sequence 47,145 cast in the McKinnon plant foundry indicated by the letter K in the prefix. I believe that in late 69' was when the format changed to the 13N100001 format.

The only thing is trying to decifer which letter is missing in the Suffix code. according to several sources it should have been a 2 letter code most likely with the missing letter being in the 1st position. does anyone have a source for the McKinnon production for 1968 or the sister site in St Katherines, Ontario? or how the McKinnon plant stamped & cast it's motors since it was also disclosed that in 68/69 GM released several changes to how the VIN stamp was done and can vary by production line.

On the plus side there is a lot of money someone put into the motor since exposing the valve cover and pulling the distributor. since the motor is up for sale i didn't want to strip it down any further, but if it doesn't sell i'll probably break it down and check out what other goodies i can find.

Originally Posted by robot

OSK....the 64 fitment is for an Impala with the "C" code. 195hp 3 speed tranny and a 2 bbl

the only issue with that is GM didn't use this casting number that early.

That 3970010 Block is a Large Journal 4" Bore Block no older then 1968 HM would be a 1967 327 ? -> Maybe could be Early 1968 L/J 327 but the Heads were off that Engine so it's hard to say with out Looking at the crankshaft #s . Also there were 2-Bolt and 4-Bolt 3970010's and the Pre-1973 Blocks had the 010-020 marked in the Front for High Tin and Nickel some L-82 Blocks after 1973 had 010-020 . By 1977 the 3970010's had White Iron Main caps . Here are some pictures of a 1971 350 3970010 2-Bolt 010-020 . Your Block is not older then 1968 .

Appreciate the info on the additional markings. If it doesn't sell as listed I will tear down the motor and check out what you posted. I know its had work done but not sure if its been bored, I'm positive its got a hopped up cam by way of the dual stage springs but id have to crack er open to see the rest of the internals. I'm so picky with my motors I just like knowing exactly what they are

Also them Heads would have cost a good amount of Money to set up with Larger valves for Performance . I had a set off a 307 Truck same casting's . The 70cc Chambers are not bad But them 1.72"in Valves at best are good for Low speed Torque / Towing and MPG Small inch Builds . But Never can say for sure Till they come off same as the pan Could be a 4-Bolt with a Forged Crank .

Decided i couldnt take it any longer to sell it without decifering the engine. the following is some pics i took during the break down process. the valve size unfortunatly was not changed from the 1.72's like i had hoped. the pistons are a .060 over stock and turns out the cam bearings were in need of replacement, go figure! there were all kinds of numbers written all over the block in paint pen that i found when stripping off the really poor paint job which im assuming was done by the machinist since most of the numbers appeared to be 0010. so based on what i found it looks like its a 350, oh well. also the front pad numbers are more clear and looks to be 1SB47145, looks more like the saginaw built motor out of the McKinnon plant. I do have all the measurements written down i took of the parts and tolerances so if i need to provide some more info i can.

The First picture here was a series of numbers i uncovered when pulling the panoilpannumbers.jpg


This is where i expected to find the cam grind number and this is what i got
cam274.jpg


these numbers are on the front of the block by the fuel pump
stampingmarks.jpg


pic of the crank, im assuming its missing a number and should be a 305/350 crank
crank.jpg


the other casting numbers on the front of the motor.
timingcover.jpg