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dan1s 09-15-2009 05:37 AM

SB suffix code
Hi, I just picked up this small block to rebuild but I can't find the suffix code anywhere. The casting numbers on the back are 3970010. The numbers on the heads are 39271 85. But on the front pad I have V0402CLY. "What is CLY"

rachet ralph 09-15-2009 06:07 AM

now for your cly suffix the C stands for car and the other stamping suffix can't really make it out but it's the date stamping for your block looks like L 10 0 the L is Dec. and the 10 is the date an the 0 on the end is for the year and by the stamp pad in the front of the block is a later block pad so i'd say it's a 1980 block so the block was made Dec./10/1980

cobalt327 09-15-2009 06:58 AM

I don't see that suffix code anywhere, either.

HEADS- 3927185....69-76...307/327/350..70cc chambers.

3970010 blocks were cast until 1979 or '80- depending on who you ask, so I'm gonna say the date is Dec. of '70, which would put this engine into a '71 vehicle. 327's were gone by then, so that would make this a 350. A quick measurement of the swept area of a bore will confirm this.

Also, it was cast in Flint, MI.

dan1s 09-15-2009 07:05 AM


That's what I came up with also. But what's the suffix code CLY from? Has anyone come seen this before.

The engine is a 4 bolt and it's a 2 bbl.

Thanks, Dan

1ownerT 09-15-2009 07:30 AM

Along with that suffix code there should have been a partial VIN stamped on the pad also, unless it was a replacement block.

dan1s 09-15-2009 08:32 AM

The pad is small. It's not like the newer engines that have a longer pad. There's not that much room for any more numbers on it. You can see by the pictures.

But how come I can't find any info for the CLY code?

dan1s 09-15-2009 11:27 AM

Is there any other codes on the block that would point me in the right direction to what it came out of.

1ownerT 09-15-2009 11:54 AM

Even though the pad is small, the partial VIN would still be stamped there. Without the VIN there isn't anything else on the block to determine exactly what it is out of. If the VIN was there it would tell you where the final assembly was done, from that and the year you can find out what models were built at a particular plant.
Without the VIN, it likely wasn't installed in a new car, or someone decked it and restamped it wrong???

Something I just ran across states that starting in 1970 the partial VIN could be stamped on the front pad, above the oil filter, or somewhere on the bell housing flange.
If you find it in one of those locations, you can determine what car it came in, but not the specific engine specs.
Maybe someone will find something on the CLY code

1964_442 09-15-2009 12:24 PM

cant find what the CLY stands for but this page may be usefull

Engine Suffix Stamping Codes Menu

rachet ralph 09-15-2009 12:49 PM

yes but after 1978 they went to a small stamping pad so the motor not no 1970 in 1970 the stamping pad was larger! so i'd still say it's a 1980 block! you could call local chevy dealer they would be able to find out i've called them before on block stampings!

ericnova72 09-15-2009 01:25 PM

You might drive yourself crazy looking for the code, but why does it matter??, you know everything about the block that you need to know. It is 4" bore(from the 3970010 casting #), it is 4-bolt main(you have verified that visually), and you know what the heads are(casting #3927185, low performance). The basic shortblock in the 70's are all the same, only slight cam and head differences, very rarely forged cranks, and even more rarely forged pistons(70-73 performance engines).

No mystery here, you have a 4-bolt 350 block, what more is needed to know??

Are you hoping you have some "rare" Corvette block, which means nothing to anyone but a Corvette restorer because the 'Vette engine is no different than a truck engine, just different valve sizes and camshaft.

cobalt327 09-15-2009 01:33 PM

Possible if they had a pile of 010 blocks left over- they quit casting then in '79 or '80, so to be in an '81 (Dec. '80 cast date), it would be a left over.

OP- do you have a carb? If yes, find the carb number stamped onto the body. If the intake is there, see what the cast date is on it, too. If there were exhaust manifolds, were they rams horns or logs?

The deal w/that CLY suffix is prolly that the engine is from a 1-ton or larger truck. The bigger trucks are not very well represented in the casting info from Mor Tec, etc. That could also explain why it was a 4-bolt 2-bbl.

I'd like to see what valves were in the heads- could be those big, 3/8" exhaust stems and might also have 1.72 intakes if they are correct for that engine and it was a truck. :evil:

Big trucks can have steel cranks so you might want to take a look to see what the parting line looks like- thin = cast, wide = forged, or look for a casting number on it.

dan1s 09-15-2009 02:48 PM

Thank you all for taking the time to help me out. I was just curious to know what type of motor I had. When I break down the motor I should know a little bit more.

Once again, Thanks


dan1s 09-16-2009 06:28 PM

How do you read the date code on the back of the block? Do you read it from the back of the block looking toward the front or from the front look toward the back.

Front looking back

From the back looking forward

Also the markings on the intake manifold are 3927183 ( 2BBL Rochester) From the info that I found this should be from 1969 307 or 327

artsvettes 09-16-2009 07:42 PM

This is interesting I have this same code CLY never did find out what it came out of.It was in a 77 vette I picked up in 05 that sat for 16 years. I dropped the pan checked some of the bearings put a new oilpump and timing set. Yeah the nylon gear teeth were cracked and put a quadra jet on it. And have been driving the snot out of it ever since. Mine is 1978 two bolt main with 882 heads and a 2bbl carb. I questioned Mortec through an email they said I read it wrong.

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