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rhb1999

partial vin and engine numbers

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I'm trying to decipher the numbers on the front passenger pad, 17K444516 and T1203CKH. The casting number is 3970010. Thanks.

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1- Chevrolet

7- Either 1967 or 1977

K- McKinnon Plant

444516- Sequential number

T- Tonawanda Engine Plant

12- Assembly Month (December)

02- Assembly Day (3rd of the Month)

CKH- I'm not sure of the year of your engine, as I only have 70-75 info. During this timeframe, this was either a 307 or 350 engine. If your engine is a 1967, this would probably be a 327, if it is a 1977 engine, then it would probably be a 350 2-bbl, but don't quote me.

My source is Chevrolet by the Numbers 1970-1975. Maybe a guy with the 65-69 book will chime in, or a guy who knows 1976+ engines will help...

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The "three place" machining codes started in 1970, cars were "C" and trucks (including pickups) were "T". That lasted for several years afterward but was finally totally "away from that" by the earlier 1980s. Prior to 1970, the machining codes were "two place" for the V-8s.

I believe the casting number would be a "generic" 4" bore block. "Generic" as it could just as easily have been built as a normal 350 V-8 or a 350 LT-1 engine . . . it's what's IN the block which defines it rather than the block casting itself.

The machining/build spec code would be in the larger numbers more toward the front of the cylinder head. The other numbers, smaller and possibly "deeper" stamps, would be very near the front edge of the pad itself, were the last segment of the VIN of the vehicle the engine was installed in at the assembly plant.

The reason I'm terming the code "machining/build spec code" is that this defines when the engine was "machined", or built, at what plant, which day, and for what vehicle's specifications. This would include, but not limited to, power rating, transmission choice, emissions specs, and which models of vehicles it could be in for a particular model year.

The DATE CODE for the block is on the block's rear extension, on the flat part, about 1/2 way between the rear intake manifold's seal and where the transmission mounting is. On small blocks, this is a casting section, about the size of my little finger nail, with the format "MDY". M = month, A=January, B=February, etc. D = day of the month, numerically. Y = last digit of the year it was cast. 1 = January, 2 = February, etc. If you know the progression of what changes were made to the block castings and when, then you can tell a 1967 small block from a 1977 small block. I'm more familiar with small blocks than big blocks, but I suspect they are similar in where the date code casting is on the block.

www.chevymania.com has "build codes" and casting numbers on their website. There are some others, too, which I believe have links on that website, which have the various numbers and codes for inline Chevy motors. In the GM parts books, you had to look through each model year's codes (cars and trucks had different books!) to find what you might be looking for. The referrenced website has them in alphabetic order.

If the stamp numbers on the pad do not match the indicated format, then the engine/block was a "replacement" item . . . for which there is no known decode for, that I'm aware of.

In later years, the size of the engine was cast into the driver's side block skirt. 5.0L = 305, 5.7L = 350 , for example. This will also have the 8 digit casting number nearby.

Regards,

NTX5467

Edited by NTX5467 (see edit history)

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Thanks, hursst and NTX5467. I'll look at the website. I'm hoping it's a '67, I understand this was the first year for the 350? This is only a block, but it looks old. The pistons have valve reliefs. A source I read said that the partial vin should have an "8" for the '68 model year instead of a "7" for this sequence of numbers.

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The 350 came out in '67, but it was a Camaro exclusive for the SS-350. Not sure what you mean about the partial VIN. Yours shows a 7, why would an 8 be mentioned or the '68 model year be mentioned when your VIN has a 7?

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Thanks, hursst. Ok, This engine has this code 17K444516, (9 characters) and it looks like '67 or '77, but the pictures on the site I looked at showed a '67 having a code 7A175291 (8 characters) and '68's with codes 18K23?80, 18B23000, 18Z137810. These having a resemblance to the code on this engine except for the second character being an 8. This is only a block, but it looks old. The pistons have valve reliefs, would a '77 350 had come with these?

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I did a little more research. Your block number 3970010, wasn't introduced until late April of 1969, meaning it had to have been from 1977. There should also be a casting date on the block, which should be at the rear of the block to the right of the casting number. It should read something like M 3 7, Meaning Dec 3, 1977, for your block. See if that is on the back of your block and that should answer the question about the date.

Also, Chevrolet started painting their blocks "corporate blue" in 1977, so if you have any blue paint left over on the block, then that's another give away.

Valve reliefs were common with certain Chev small blocks during the era, while others didn't have them. Depends on the application. Hope this helps a little.

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I have no doubt it would be a 1977 model year motor, given the three letters at the end of the "machining code".

Historically, "valve reliefs" might have started in the earlier 1960s, when camshaft lifts increased during the "high compression" era, BUT the piston in the 1971 Chevy 350 was what I term "4 valve cut-out, dished and beveled" piston in them . . . with the rated 8.5 to 1 compression ratio and 76cc combustion chamber volume cylinder heads. This same configuration piston was also used in the 1986 Corvettes with aluminum cylinder heads (smaller combustion chambers and 9.5 to 1 compression ratio).

The -010 small block casting was pretty much common in the 1970s. It could make a 302 or 350 depending upon which crankshaft/piston combination was inside the block, of a 350 2bbl or a Corvette L82 for that matter, too. Or if the main journals were the same size, a 327. Different strokes would mean different piston "compression height" for a constant "deck height" or compression ratio in the engine. I also believe it could be either a 2-bolt or 4-bolt main block, depending upon how the main cap machining and such were done?

Remember, it's the "machining code" which defines what the engine was built to go in and what other items were attached to it to make the completed engine assembly "hanging on the hook at the assembly plant". The smaller stamp is which particular vehicle it resided in.

ONE thing to be aware of, when buying ANY used short block/engine . . . there should be some stamping on the tops of the pistons, hopefully, which might be ".030" (or similar). This will identify the piston as .030 oversize, which means the engine has been rebuilt at some point in time. The cylinder walls were bored .030" (a very common over-bore size for almost any engine) to get to "fresh metal" and remove any wear patterns from the cylinder walls in the process. Somewhere in the middle 1970s, the block castings were more "thin wall" in nature and would reliably support ONLY a total of .040" over-bore, rather than the earlier .060" max over-bore. In other words, this "block" you've found, which you seem to desire to be a 1967 (for whatever reason), could just be good for nothing more than a huge boat anchor. Of course, it could be disassembled, vatted, and then possibly bored to .040" (with the appropriate pistons) . . . hopeing it will "clean up" at that minor over-bore amount. This is something that might be a "crap-shoot" or that only an experienced engine builder might estimate.

The OTHER reality is that once the engine is asssembled, NOBODY will know if it's a '69 350 in a later vehicle or a '77 350 (in any vehicle) as it's the way the engine is "dressed" that would define the model year, visually, or what vehicle it came out of (as to which side the a/c compressor is mounted on, which also affects which side the alternator is mounted on), where the oil filler is located (a front tube and cap or in the valve cover, and which side valve cover), the which intake manifold, which exhaust manifolds, which type of distributor, etc. Therefore, you could have a normal 350/300 4bbl (QJet) V-8 from 1969 or a 1986 IROC-Z TPI 350, or a 1969 C-10 350/255 QJet 4bbl V-8 . . . all from the same engine, depending upon the variables I mentioned.

Historically, there is NO allure to a '67 350/295 Camaro V-8, other than IF you have a '69 Camaro SS-350 that is "matching numbers", or similar. Internal "guts" were the same, except for compression ratio, all the way through about 1979 (or later). Same cam, same valve sizes, for example. Different emissions specs to meet, which affected the carb/distributor sort of calibration issues and the compression ratio.

BUT . . . if in the process of getting any small block Chevy engine (or the big block, too, I believe) rebuilt, you really go out for having everything "correctly dimensioned", you get the cylinder block "decked" (where the deck surfaces, where the cylinder heads seal against and attach to), that machining operation (usually with some sort of rotary lathe) will "wipe" all of those stamped numbers off of the block. Without those stamps on the pad area, that 4" bore block becomes "just a 4" bore block" -- period. For example, it can make a '67 Camaro Z-28 302 V-8 "DZ"-stamped block (which used to be worth $$$$$ in a '67 Z-28 car!) into just a normal 4" bore block, which might have been a 350 2bbl V-8 in its prior life. Who's to say that many of those earlier Z-28s, which were raced, had that "blueprint" operation done, not knowing it would affect the later ultimate value of their car, not being able to verify "numbers match" (or "stamp codes" match)?

I've also known some Chevy enthusiasts who clamored for the storied "double hump" small block V-8 cylinder heads. Again, these were "maching operation identifiers", before we knew to look at casting numbers. Just as with the later paint codes, it was an easy way for those building the engines to quickly and visually get the correct heads on the motor they were assembling at the engine plant. And I also know of one "collector" who used some body putty and turned a set of earlier-model Chevy small block heads into "double hump" heads for a (slobbering over them) local enthusiast . . . even using some sand to texture the putty before it was painted. One laughed and the other one didn't, when the heads went to the machine shop's hot vat.

In the world of small block Chevy cylinder heads, the normal 1.94/1.50 head castings could also be machined to accept the HP engines' 2.02/1.60 valves, BUT the key point is that the factory-produced heads also had a "relief cut" into the side of the chamber, by the intake valve, to "unshroud" the intake valve some the larger valve would really breathe better. Similarly, a "police" or "HD" head could be the same casting, in particular model years, but with larger-stem valves installed. Again, a machining operation on the same casting number head. OR it could be a "HD" truck head, with 1.72" intake valves rather than 1.94" intakes! Or a 327/250 head (1.72" intake) which would have 1.94" intakes for the 327/300 motor. Just some examples of how a common casting, with a common port size/arrangement could be used on a multitude of different-spec engines for Chevrolet vehicles.

SO . . . go into this engine deal with your "eyes wide open", for best ultimate results.

Respectfully,

NTX5467

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Hi. I was hoping I could find some help. I have an 89 iroc z28 with an after market engine. Behind the alternator is 13w302287 then the number starting with v is to faded to read. The 3 may be an 8 but best I can make out is 3. Need idea of what engine I have. Please and thank you

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Hi Guys, I have a 1972 K5 Blazer without the original motor and trying to id this thing.  Hoping someone here can help.

Engine casting:  3970010  -  should be a 69 - 79 car, truck, or vette

Engine Stamp:    V0914TKB - Built in Flint, MI on Sept 14th  76-77 K10 ?

Engine partial VIN:  C7Z121682  -  is this from a vette ?

Heads:                    3932441   -   69-72  327/350   1.94 intake, 1.50 exhaust

 

What I'm wondering is the partial vin with a 'z' in it.  does not sound like a truck motor to me.

Is it?

Thanks,  JD

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