Ok folks, here's a puzzle, at least for me. I bought my 72 stingray and brought her home from Washington last week and have been going over it with a fine tooth comb ever since. When I bought it, the seller told me it did not have the original motor. He couldn't offer much info on it since he only took it in as partial payment for a 67 he sold a guy. The car originally came with 350 cid, 200hp, 4spd posi and is a pretty base model. The engine plate on the shift console shows engine to be 350/ 270hp with 360ftlbs.torque. I pulled the valve covers today and the heads' numbers match the late 72 vette with 350/200and 255Hp. After spraying a lot of gunk off the right front bank of the block, I located the assembly date stamp T1212CMJ. Now I know the T is for Tonawanda where only GM big blocks were made and it was assembled on the 12th of December but I can't find a code anywhere to identify CMJ. I'm looking in Richard Prince's 68-82 Corvette Resto guide. The block casting number on the rear left of the engine shows as 3970014 which is supposed to marry up to late 72/early 73 BUT the block casting date above it is L10 74 indicating cast date of December 10 1974. So I have a big block matching a casting number for a late 72 early 73 but casted in late 74. There is no VIN derivative number by the assembly date stamp. I had heard that you could special order a short block that would be void of the VIN derivative stamp for the corvette. I assume if this is true, one of the previous owners, for whatever reason, dumped the original block and ordered a mark IV short block, but I have no idea about the console i.d. plate, I can't find any info on a 350cid with 270HP. I hope this doesn't sound like the rantings of a crazed man but hope someone out there can shed some light on this. Any and all thoughts would be much appreciated.

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Keith,

Looks like you have a small block 350 cast between 1970, and 1976. Here is a link to casting numbers: http://www.mortec.com/castnum.htm

Hope this helps!

Bill

Keith, here is what I found.
The suffix CMJ was a 1974 350cu.in. 9.0:1 CR Turbo 400 tranny Police package/full size car. I'm not sure of the HP, but I would have to say about 250hp. That is the highest hp rating for a '74 350 that I see.
The CMJ suffix was again used in 1980 for a 305 cu.in w/AT.
Hope this helps a little.
Sarge

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GEN III 5.7L "LS6" Engine swap
TKO500 5 spd.

Thanks, Bill. I'll have a look at the site. Like I said, according to the casting block date, it was cast on December 10 '74 and assembled Dec. 12 at Tonawanda but what is throwing me off is that I was under the assumption that Tonawanda only cast the big block. Can you marry up 350 stock 72 vette heads to a big block 75 engine? The other thing that is throwing me is the engine code on the assembly date stamp. Does anyone know what engine code is CMJ? Will check that site in the meantime, Bill.....Thanks

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Appreciate that, Sarge. Got your answer while I was typing back a reply to Bill. Where did you find the code breaker for CMJ?, and (I hate to sound like a broken record, but numbers can be a real pain in the a..)
what is a 350 doing being built at Tonawanda? From what I have read, they only built the 427 and 454. Eh, what??

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Small block heads will not bolt up to a big block.
And Tonawanda Engine made many small blocks as well as big blocks. A friend of mine worked there in the late '60's thru the '70's on the 307 and 350 V8 line.
Sarge

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GEN III 5.7L "LS6" Engine swap
TKO500 5 spd.

I owned a '69 350/300hp that I pulled from a rusted SS Chevelle and it was from Tonawanda, had a foil "Tonawanda 300HP 350" decal on the valve cover also. Actually I still have all the pieces from tearing it down .

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'76 L48 Auto Project |IMG|http://www.freewebs.com/privategod/Mine2a.JPG |/IMG|

Ok, guess that goes to show that just cause you can write a book, doesn't make you an expert. Thanks for the info on Tonawanda, guys. Sarge, this block was definitely cast and assembled in December 74 so can't imagine it going into a '74 - more than likely a '75 don't you think? This little vette o'mine is going to take a lot of questions and answers. Really appreciate all the input. By the way, I traced the Q-jet on it to a 1982 305 pickup. Is that a match made in heaven or hell, or does it make much difference. Good thing there's snow on the ground up here.

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Keith,
Being traced as a "Police" engine, it is possible that they may have had a mass order for '74 Police packages. So they may have extended the run to fill the orders.
I don't know if the police cars back then were emission exempt in '75. Remember that the catalytic converter came out in '75. If they were exempt then I could see them sticking the remaining "CMJ" engines in a few of the first '75 cop cars. But I doubt that is the case.
....and the mystery continues
Sarge

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GEN III 5.7L "LS6" Engine swap
TKO500 5 spd.

Well, knowing how anal I get when things aren't 'up to snuff' I will probably end up yanking the engine and tranny since the car is sitting right by the hoist. The entire car needs a good swabbing out and detailing in any event and probably wouldn't hurt to take a peak inside that ol' block. Who knows what evil lurks there...the Shadow do. What we get ourselves into (midlife crises?)

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1969 427ci,400HP Turbo hydromatic (M40),L36 engine,Holly 3x2-BBL,T/I has an engine code suffix of MJ

In 1970 the letter C was added to the code to designate Chevrolet Motor Division.

Still leaves a mystery!!!! sorry I cannot be of more help.

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My Two Babies!!!!

Think I'll try to find a site for GM and hopefully they can fill in the blanks. Will let you know if and when they come up with anything.

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MAN.........You sound as bad as I am.
Maybe I can help you piece together your mystery.
Although there are some pieces missing.
What is your VIN 5th digit?
*3970014 was 1968-1976 car & truck 350ci/2 bolt main.
*350ci/270hp was the 1971 corvette base engine.
Sounds like your block had to replaced and they used the original heads and intake.
What about your intake #.?

Ya, but ain't we havin' fun? The engine digit in my VIN indicates (K) that the original engine was a 350/200Hp
but I'm sure the block was exchanged while keeping the stock heads. Original intake manifold is gone with an Edelbrock performance in place. Does anyone have a web site for GM that would be able to supply the key to this great mystery?? Keep on a'pluggin at it guys, I'm sure we'll get to the bottom of this sooner or later.

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Well, I couldn't sleep the other night so was up leafing through my interchangeable parts manual when, lo and behold, it jumped right out at me!! CMJ is from a 1974 350CID Impala with 195HP so is running close to the original 200HP block. Sarge, you get the prize for the closest shot. In any event, will be pulling the engine early next year and doing a total tear down and rebuild with the idea of bringing in some more substantial horsepower than what exists and also ensuring the engine is 100% before it hits the pavement in the summer. Thanks for all the input, fellas, and Merry Christmas. Have no idea how Santa is ever going to get that sleigh airborne with all those vette parts loaded on it.

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FYI...In 1972 the 454 was rated at 270 hp... Engine codes end in CPH, CPJ, CSR, AND CSC.

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sstanford '76 L48

Keith,
Thats cool man, that you also found out what it is.
So um....where is is my prize. Just teasing.

Merry Christmas
Sarge

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GEN III 5.7L "LS6" Engine swap
TKO500 5 spd.