VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Engine Identification

I know there are dozens of posts on this topic on this site and there are literally hundreds of sites on the topic. But, in short I've searched for hours and don't have an answer for my question. We (my mechanic) have just built an engine for my recently purchased '64 Malibu SS. The block was provided by the machine shop.. I'm trying to get as much information on the engine as possible. Some of the numbers are easy to research. Others I have found are near impossible. Here goes.
Block casting #3970010. Cast date code-I228=June 22, 1978. Based on these numbers I've decided my engine block came from a 1978 350 ci hp-185 to 370 2 or 4 bolt main trk, van, Vette. (Mine is a 4-bolt). Now here's the question. There are two other numbers stamped on the block in front of the right head. They are C97118082 and 23087. I can find nothing on these numbers. I'm assuming one is a partial VIN from the original vehicle but it doesn't seem to fit any of the formats I've searched. This is mostly a curiosity. It won't change anything. I'm turning to my VCCA friends for help. Any help would be appreciated.

What I have been told and read is that the right side of the block (looking from the driver's seat) has a pad that in the 70s had the last several digits of the original vehicle serial number. All of my Chevy passenger car blocks (two bolt main caps) from that era have it. That can explain the five digit number.

That doesn't explain the other number. The high performance and truck blocks were four bolt. Maybe the C indicates 1/2 ton two wheel drive truck? That is pure speculation.

Thanks Chipper.
Here's the stamping in front of the passenger's side head. The V1004TBM is the plant (V), assembly date (1004= Oct 4th) and application (TBM). The other two are a mystery.

Yup, mystery to me as well. Anyone else want to try to explain?

beautiful factory horizontal broach marks. i'd guess the 23087 was stamped by a auto machine shop( ie, their work order #). V== flint machine assembly plant. 1004 is the date the block was machine(october 4th) i think olesarge misinterpreted the casting date. the casting date in the opening post reads I 22 8 which would make the block cast on sept 22 of 78. that would make for an approximate 2 week interval between cast and machined(which is typical interval) . as far at the suffix of TBM, i can't find that anywhere. not in the Motor manual of 1980 under chevy, olds or pontiac, all three of which used the 350 ci chevy blocks. let us know if u figure out the application of TBM . mike mccagh

Based on the information I an find I agree that the casting date is 22 Sep 1978 for that casting number That casting number was used for many years and could be a 2 or 4 bolt main block.

I found a reference to the "TBM" but that source indicates it was only used on some special truck engines from 1970 through 1974. That would not make sense for this engine as a 1978. It would not surprise me if codes were reused. The source I was viewing did not show it applied to later years. Or they could have used the code for a different meaning in later years.

For the 9 character string I expect that the last 6 digits are the last 6 digits of the VIN. I would investigate the possibility that this engine went into a 1979 vehicle. I doubt if they were machining blocks for 1978 vehicles in October 1978. The other clue that this might be a 1979 vehicle is that the sequence number is relatively low. Most factories started their sequence numbers at 100,000 or 300,000, or something like that. So this could have been the 18,082 vehicle produced in 1979.

The C97 makes sense also. The first position is a "C" for Chevy. The second is the year which makes sense as a 9 for 1979. The third is the assembly plant which in this case would be Lordstown. Lordstown was building many different vehicles in 1979.

Maybe this was an engine for a Chevy van.

Thanks. A lot of what you're saying coincides with what I found. It's just that so much of it is guessing.

Here's a screenshot from hotrodder.com. This agrees with what I've seen elsewhere.

Here's another screenshot from nastyz28.com.
TBM indicates the engine is from a 1979 C-20 or 3500 van which agrees with everything else I've seen. But that still doesn't explain the other two stampings.

Well anyway, here's what it looks like installed.