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74 454 engine numbers

74 454

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Apr 25, 2007
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31
Location
Michigan
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1974 Brown Coupe 454 4-speed
I pulled the numbers off my 454 at the front passenger side just below the head on the little flat machined self. One of the numbers match the VIN 14S413210. So it's the original block. The second number was T1128CWM. Does anyone know what this number is? I can't find anything online. Did I copy it wrong? I know the T and the 28CWM is correct. But the 11 could it be II?
 

KOPBET

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Jan 31, 2003
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1,355
Location
Tulsey Town
Corvette
'73 Silver LS4 4 speed
I pulled the numbers off my 454 at the front passenger side just below the head on the little flat machined self. One of the numbers match the VIN 14S413210. So it's the original block. The second number was T1128CWM. Does anyone know what this number is? I can't find anything online. Did I copy it wrong? I know the T and the 28CWM is correct. But the 11 could it be II?

T = Tonawanda Plant
1128 = 11/28 date code
CWM = 73/74 454 mated w/manual trans
 

74 454

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Messages
31
Location
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Corvette
1974 Brown Coupe 454 4-speed
Big Block Casting Numbers

Just pulled the casting number on the driver rear of block, 3999289. Different sites tell me different things, 71 to 79 or 72 to 78. All say it's a 454. Can this tell me if it's a 2 or 4 bolt main? It also had a large P or F by it. Then on the next surface up there was GM T12. Does this tell anything?
 

KOPBET

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Joined
Jan 31, 2003
Messages
1,355
Location
Tulsey Town
Corvette
'73 Silver LS4 4 speed
From the info I have, the 3999289 is the 454 2-bolt main block used in the 1972-1974 Corvettes. 1974 was the last year for the 454 in the Corvette but the 3999289 454 was probably used in some other GM applications in the same and later years.

I'm not sure about the other marking, but I'm guessing it is actually GM 12 T rather than GM T12. My block has GM 9 T. It was born in Sept, 72 at the Tonawanda plant. By pure speculation I am guessing the 9 is the month and the "T" is the plant. In a previous post you have the numbers from the stamp pad (e.g. T1128CWM) so that may hold true. Someone will let us know.
 
Joined
Jan 1, 2002
Messages
7,246
Location
Washington, Michigan
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'67 Marina Blue Convertible
That block was used from '72-'79 in all 454 passenger car lines, trucks, and Corvettes, and in all applications had 2-bolt mains; the GM 9 T and GM 12 T are Tonawanda foundry pattern numbers, for internal traceability. The block casting date is located on the rear flange of the block, near the casting number, and will be a letter followed by two or three numbers, like C 12 8 (for March 12, 1978).

:beer
 

74 454

Active member
Joined
Apr 25, 2007
Messages
31
Location
Michigan
Corvette
1974 Brown Coupe 454 4-speed
Thanks everyone for your help. I think I'm all set now.
 

74 454

Active member
Joined
Apr 25, 2007
Messages
31
Location
Michigan
Corvette
1974 Brown Coupe 454 4-speed
Thanks everyone for your help. I think the numbers are correct and match up.
 

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