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I need a chevy small block engine decoded

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casting code
7K views 6 replies 5 participants last post by  cdminter59 
#1 ·
Block numbers is 3970010
Head numbers is 3870126

If you could decode this it'd be most appreciated. Thanks
 
#2 ·
I have a Chevy Small Block Parts Interchange Manual by Ed Staffel, SA Design Books.
It shows this casting number was used for 3 different engines:
1. A 1969 302 with 4 bolt mains in a Z-28 Camaro
2: A 1969 327 with 2 bolt mains in trucks and industrial engines
3. A 1969 thru 1980 2 or 4 bolt main in most anything on the assembly line.

Head
The head number doesn't appear in my book.
 
#3 ·
The 126 castings came on 327 and 350 engines from 1967 to 1970.
They have 1.94 intake and 1.50 exhaust valves. None of the sites list a chamber size for these heads however by looking at a picture they appear to be 74cc's. They likely don't have hardened exhaust seats and they also may not have accessory holes.
 
#5 ·
On 09/29/2012 at 04:43 pm, I gave all the infomation to ID this block in a thread titled Chevy Engine Module Number on page 2 of the engine section. Someone has moved the thread also.
All the engine ID threads get moved to the Basics forum.

Block numbers is 3970010
Head numbers is 3870126

If you could decode this it'd be most appreciated. Thanks
For future reference, info on deciphering the castings, etc. of Chevy engines can be seen here.

Good luck.
 
#7 ·
Small block chevy engine decoded

Quote:
Originally Posted by fordss
block # 3970010 head 3870126 and k11 12 cnu ? don't know what that is thanks
K= St. Catherines, Ontario, McKinnon Industries, Canada.
11=November, 12= day of month. CNM= 1970 350 powerglide, 250hp, 2B carb, A= Chevelle, F= Camaro, X= Nova/ Belair/ Kingswood. 3970010 = 350 2/4 bolt mains, 1969-1979. 3970126 = 327,350, 1967-71, 1.94 intake 1.5 exhaust, The number 3870126 does not exist.
 
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