Help Identifying Block - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1970 CST · 09-22-2025, 06:02 PM

My truck which is supposed to have a 350 currently has an older 305 in it. While scanning FB market Place I saw an ad for a 350 engine out of a 1970 Chevy pick-up. I picked up the motor, less an intake for $250. Looking over everything I am confused by the numbers.
Casting - 3970010
Center of Block below intake - M (in a square) followed by 6
R/F of Block - K11 05 TBB

The question I have is the TBB can either be a 1970 C10-3500 or a 1979 C10-2500?
On the right side of the block there is the following.
A 1
D < N
Any help would be appreciated.

09-22-2025, 06:02 PM	#1
1970 CST Registered User Join Date: Mar 2021 Location: New Paltz NY Posts: 66	Help Identifying Block My truck which is supposed to have a 350 currently has an older 305 in it. While scanning FB market Place I saw an ad for a 350 engine out of a 1970 Chevy pick-up. I picked up the motor, less an intake for $250. Looking over everything I am confused by the numbers. Casting - 3970010 Center of Block below intake - M (in a square) followed by 6 R/F of Block - K11 05 TBB The question I have is the TBB can either be a 1970 C10-3500 or a 1979 C10-2500? On the right side of the block there is the following. A 1 D < N Any help would be appreciated. Attached Images



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