Help with sbc engine suffix id

[ScottH]

I've come across someone with two 350 engines for sale and have no way to id what their original application is. The casting on both is 3970010 so I know they are 350s. The suffix is:

1 - CMJ
2 - TEC

Any info is greatly appreciated!!!

[bpmcgee]

CMJ -- 1980 305 Automatic Camero
TEC -- 1957 283, M/T w O.D, 1/2 ton truck (my guess is you misread this one).

So they're both small blocks, but NEITHER of them appear to be 350s

That casting appears to have been used a LOT, from 69-80 at least, and in 302, 327, and 350 applications. Remember that all these engines share the same basic casting, but they were assembled differently.

Brian

[1971LT1SWBPOSI373]

Brian, can you tell me what "TJA" is.....
I know the T denotes truck engine, but I have been try to find out what the JA references.

Your right about the block casting numbers, they are used quite frequently on just about anything built during those years. He may also want to get the casting numbers off of the heads to get an even better idea of what he has to work with! TJ

[MJN]

TJA= truck '73,'74,'75, and '79 350, 155hp in '73 160hp in '74,'75 165hp in '79; '73 th400 tranny, the rest had manuals, all ls-9 RPO's, single four barrel carb
'73 came from 20 and 30 series truck C/K
'74 from 10 and 20 series C/K
'75 from 10 and 20 series C/K
'79 from 30 series P van


ScottH: CMJ= '91 Cadillac 350, 185hp 700R4 tranny, TBI
'75 Chevelle, 350 145hp L-65 RPO 350tranny single 2 barrel carb
'76 Chevelle, 350 145hp same as '75 Chevelle
'74 Impala 350, 155hp single four barrel carb, 350 tranny, police edition
'75 and '76 Impala 350,145hp,350 tranny, single 2 barrel carb
'80 Impala, 305 155hp,350tranny, single four barrel carb

[1971LT1SWBPOSI373]

Thank you MJN!!!!!!
Mine is a 1975 350.
The head numbers gave it away!!!!!!!!!!!! Thanks, I now know my tune up info!!!!!!!! TJ

[ScottH]

Thanks to all for the info.

MJN, I always thought that a block with the casting number of 3970010 was only a 350. Would you know if this is a correct assumption? Also, would the head (again, assuming they are original) numbers help to narrow down the original application?

Thanks again!

Scott

[MJN]

3970010= 350 '69 Corvette late '69 4 bolt main
302 '69 Camaro z/28 late '69 4 bolt main
350 '69-79 truck, passenger, chevelle,camaro,nova, monte carlo, 2 & 4 bolt main
350 '70 corvette 300,350, 370hp 4 bolt main
350 '71 corvette 270,330hp 4 bolt main
350 '72 corvette 200,255hp 4 bolt main

Only 302 and 350's had this number. The heads might help, they would tell what block they are attached to or were meant to be attached to, what year, the truck or car, valve size, and a few other things. Post what the number is and I'll check it out for ya.

All numbers are looked up in the Cars and Parts Magazine Catalog of Chevy V-8 Engine Casting Numbers 1955-1993 and stamped numbers. Suffix codes are from the MSR-1 Chevy Small Block Factory Engine Identification Code Guide Suffix Codes 1955-1999.

[bigjimzlll]

3970010....327.....69....2...Trucks and industrial

[jhow66]

CMJ was also used in '74 for a 350 with turbo 400 in a full size police car. Block casting # 3970010 was used from '69-'79. Check block casting # on the TEC-it shows to be a 283 as Brian says.

[lukecp]

www.nastyz28.com

Go to the numbers decoding and look at "Small Block Chevy Suffix Codes" and it lists the codes of all the letter sequences stamped on the engine. Also has the numeric block casting numbers.

[Sweet72]

I've exhausted all resources trying to find info on the suffix code TRD on my 3970010 '72 block.

[Blazer1970]

Originally posted by Sweet72
I've exhausted all resources trying to find info on the suffix code TRD on my 3970010 '72 block.

TRD is a '72 350 4bbl. 175 net hp stock. Originally installed in a van or bus application - C30 & 3500.

[Sweet72]

Ooops, shoulda looked at my block again last night before I posted...It is TND not TRD.

[MJN]

TND= '92 truck, 350, 210hp, manual tranny, TBI, 10 and 20 series C/K L-05 RPO code

[Sweet72]

MJN,
3970010 blocks were cast from 1969 to 1979 or 1980 according to MORTEC and NastyZ28.com. The casting date on the block is E242... E=May, 24=24th, 2=72. Also, it has the two piece rear main seal. Thanks

[MJN]

according to my book it is a '92 block. I know the 3970010 block was only cast until '79. Either the suffix is wrong or had been restamped. Otherwise Blazer1970 is correct since TND is a '92 block.

[ScottH]

Thanks again to all who responded, great info as usual!

I'll check on the head numbers this weekend and post them.
Also, can u tell me where I can find the date casting numbers on the block?

Scott

[Sweet72]

Small block casting date is located on passengers side rear of block on flange forward of bellhousing. Big block on the right side of engine above the oil pan rails. Didn't mean to hi-jack your thread Scott, just wish I could decode my 350 block.

[ScottH]

Sweet72, no problem here, ask away. That's one of the many things that's great about this board, we all share info.

Scott