What motor do you have casting gm 3970010 index c6a124450 vo7128tkb?

The casting number GM 3970010, along with the index C6A124450, indicates a Chevrolet small-block V8 engine block. However, that casting number alone doesn't specify the *exact* displacement (e.g., 350, 305, etc.). The number only tells you the basic block casting.

The additional markings (VO7128TKB) are likely plant codes and date codes which help pinpoint the production details but are not sufficient to isolate the exact engine displacement without additional information from a vehicle identification number (VIN) or other documentation relating to the specific vehicle.

To determine the precise displacement (350 cubic inches, 305 cubic inches, etc.), you would need to:

* Check the engine itself: Look for markings on the engine's valve covers, intake manifold, or other components that might state the displacement.

* Check vehicle documentation: If you know the year, make, and model of the vehicle this engine came from, you can find the engine specifications in a repair manual or online databases.

* Consult a VIN decoder: Using the vehicle's VIN, you can usually determine the original engine specifications.

In short, the casting number provides a clue, but further information is required to identify the exact motor size.