47-59 What does this engine stamp mean?

[RostaRob]

In my 58 Apache I think I have a 350. The only stamping I can see is on the front passenger side and I think it reads V0321CMJ. Can someone make sense of this?

[geezer#99]

You’ll find cmj in here.
Good and bad possibilities.
Could be a 350or 305.

https://www.nastyz28.com/gm-chevy-co...s-suffix-2.php

The V means it was built in flint on March 21.

To determine what it is, lookin here. Info plus pics where to find your motor casting numbers.

https://www.mortec.com/

[geezer#99]

You can also tell what motor by the pad size.
That’s in case you can’t see the casting number.

https://www.crankshaftcoalition.com/..._Chevy_engines

I’m leaning towards it’s a 350.

[RostaRob]

Pad size?

[geezer#99]

The pad your numbers are on.
You can tell by the length of it.
Look in the link.

[mr48chev]

You are going to need the casting number off the block behind the head on the left side of the engine to figure out exactly what you have

CMJ can be 74 Copcar 350 or it can be an 80 305 out of a Camaro

https://www.gregwapling.com/hotrod/m...rs-ce-cmj.html

NastyZ28 which is one of the go to sites for engine number decodes for chevy says the same thing https://www.nastyz28.com/gm-chevy-co...s-suffix-2.php

Their main page for suffix numbers

https://www.nastyz28.com/chevy-engin...-stampings.php

The lime book says that there are several rigs with a CMJ suffix.http://www.camaros.org/pdf/LimeBook.pdf

[RostaRob]

Thanks for the info. I’m going to see what else I can find today but now that I think of it I remember the PO (2nd owner) telling me that they bought the truck from an old guy that had worked for the WA state depot forestry and he had purchased this work truck from the state. So I’m thinking/hoping that while working for the state he may have been able to procure a cop car engine somehow….making it a 350.

[mr48chev]

No he would have bought the engine out of a wrecked cop car from the wrecking yard. I don't know about down in Battle Ground but here there are dozens of old ex cop cars running around driven by local folks who have the misguided idea that they are well cared for and great cars to have and many more of them hit the auctions and end up in the wrecking yards. Even if the guy worked for the state he would have to buy the engine or donor car from a state auction https://www.govdeals.com/index.cfm?c...45&redirecting

Same thing with working for the federal govt, When I was working for TSA I bought a Stainless steel Work Table from TSA through the GSA auction and had to go pick it up in Pasco. I bought other things though the GSA auction including five file cabinets for a 12.00 Bid out of the Wenatchee Social Security office. The heavy file cabinets make great tool and parts storage in a garage.

Back to business, along with the suffix number you need the block casting number to actually ID the engine. That as I said in post 6 is on the back left hand corner of the block between the head and the bellhousing. It will be in the spot shown here in this photo I snagged off the net becasuse I couldn't find my photo of one.

If you can see back there get the number and write it down and then check it against a casting number listing like this one https://www.nastyz28.com/sbchevy/sblock.html

I have used my camera or my phone to aim down at it and get the image that I can read the number off several times. That matched with the suffix number should confirm what you have.

[RostaRob]

Here is what I found on the back of the block-3970010 and what I think is the “casting clock”? By the chart the 7 digit number shows either a 1968 327 or a 1969-1979 350. ??? So paired up with the other numbers does this confirm anything? The pad is the larger 4 inch or so size.

[mr48chev]

Three fiddy block. at least it is a 4 inch bore block so the 74 350 should be pretty well spot on especially if it has a stock chevy distributor with points.