74 454 engine numbers

[74 454]

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]

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

 

[6880 Mike]

....But the 11 could it be II?...

Yes, it could. Sometimes the capital letter I was substituted for numeric 1s. It's entirely possible what you think looks like II could actually be II.

 

[74 454]

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]

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.

 

[JohnZ]

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).

 

[74 454]

Thanks everyone for your help. I think I'm all set now.

 

[74 454]

Thanks everyone for your help. I think the numbers are correct and match up.