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.

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

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

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??

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

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 .

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.

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

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?)