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SBC identification help 305 or 350

23K views 7 replies 6 participants last post by  Joe_T 
#1 ·
Trying to id the engine i have in my 52. The guy i got the motor from said it was a 305 but i got to looking and the engine code at the drivers rear of the engine was 3970010 and the code at the front passenger side behind the alternator was k1110 cmj. The info i found online for these numbers said it could be a 1974 350 or a 1980 305. The date code on the pass. side bottom was K 28 a2 dn (i think) i couldnt read it very well. Any ideas?
 
#3 ·
The number code from behind the alternator tells the application and GM re-assigned these #'s to different applications and engine sizes sometimes, usually several years apart.

However, the block casting # tells the true tale, that # is a 4" bore block used to make '69 302, '68-69 327, and the most common use--'69-80 350. This # 3970010 eliminates the possibility of it being a 305, so it looks like you have a 1974 350. Probably the most common 350 casting # ever made and will be found machined either for 2-bolt or 4-bolt mains, you won't know which without pulling the oil pan to look.

www.mortec.com for casting # codes.

Sounds like the previous owner found the application code in a book that matched a 305, didn't discover that it was a reused code # also used at an earlier date, and didn't use the block casting # to verify what he had, or he would have found it to NOT be a 305.
 
#4 ·
leadsled7 said:
Trying to id the engine i have in my 52. The guy i got the motor from said it was a 305 but i got to looking and the engine code at the drivers rear of the engine was 3970010 and the code at the front passenger side behind the alternator was k1110 cmj. The info i found online for these numbers said it could be a 1974 350 or a 1980 305. The date code on the pass. side bottom was K 28 a2 dn (i think) i couldnt read it very well. Any ideas?
Came across this post whilst doing some research trying to identify an engine I have just got hold of.
Its also 3970010 and has a K1107CMJ code, but I can't find a Date code I have looked in the normal areas at the back of the engine over from the Casting number, but the engine is still quite built up and a bit grubby where exactly was your date code? was it raised up and quite visible.

Mine has 3932441 heads and a partial vin of 16B472500 but I think I can make out under one of the manifolds upside down *5**L which got me thinking its a 5 Litre.

I will strip it at the weekend to have a look, but I will need to prove the date for our emission regs in the uk, any advice will be appreciated.

Thanks

Joe
 
#5 ·
Joe_T said:
Came across this post whilst doing some research trying to identify an engine I have just got hold of.
Its also 3970010 and has a K1107CMJ code, but I can't find a Date code I have looked in the normal areas at the back of the engine over from the Casting number, but the engine is still quite built up and a bit grubby where exactly was your date code? was it raised up and quite visible.

Mine has 3932441 heads and a partial vin of 16B472500 but I think I can make out under one of the manifolds upside down *5**L which got me thinking its a 5 Litre.

I will strip it at the weekend to have a look, but I will need to prove the date for our emission regs in the uk, any advice will be appreciated.

Thanks Joe

In-so-far as displacement is concerned the only number that counts is the block casting number. Numbers from other parts including heads and manifolds may or not be native to the bottom end. 305 heads and manifolds will fit onto a 302, 327, or 350 bottom end as well as others.

The ---010 block is a highly desirable heavy duty block that was used in high performance vehicles, trucks, and industrial equipment where extra strength was required. All of these block are a 4 inch bore and were used in the 302, 327 and 350 engines. 305 blocks have a smaller bore and smaller cylinder tubes that cannot be taken to the 4 inch size.

The ---010 block comes with 2 or 4 bolt mains, some late 302's got them with 4 bolts and many thousands of 350's did from Corvettes and Z28 Camaros to pickup trucks. 327's are generally considered to have only come in 2 bolt mains; but knowing GM like I do, I wouldn't be surprised if somebody, somewhere, someday opens up a 327 with a set of factory 4 bolts in it.

Bogie
 
#6 ·
The trouble is this could be a 4 bolt 350 sort after 13970010 engine, but to put the car on the road in the UK the engine has to be dated to identify what emission regulations to apply to the car.
If the inspector can't date the engine based on the info provided I am stuffed :nono: and will have to find another block if I want to use it on the road.

Hence I need to find a date code casting...
if this block hasnt got one I will need to proves some dont have them...
And in the case of know date code a combination of ID casting number can prove the date.

Trouble is they don't like stamped numbers preffering cast ones. :confused:

Thanks

Joe
 
#8 ·
I have seen the listing from nastyZ28

But also from Chevymania


CMJ 75 350 Impala 145 L-65 TH 350 2-Brl A.I.R.
CMJ 75 350 Chevelle 145 L-65 TH 350 2-Brl A.I.R.
CMJ 80 305 Impala 155 LG-4 TH 350 4-Brl
CMJ 91 350 Cadillac 185 L-05 700R TBI

Would the fact that all of the above only list one year of manufacture each be the reason for no date code?

None of the above would satisfy an inspector unless it was on Chevy headed paper :pain: or one of the nominated engine builders would sign it off. Plus the block has to be before july 75 to pass :( so a date of 75 would need the exact month also.

Thanks

Joe
 
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