It's probably a 1972 350.
It is an excellent GM block.
The code "GM 37 3970010" likely refers to a specific part or casting number associated with a General Motors engine block, particularly from the year 1937. The "GM" indicates the manufacturer, while "37" specifies the model year. The number "3970010" is a casting number that identifies the block's design, specifications, and compatibility with certain GM vehicles. This number can be used to find more information about the block's history and applications in GM cars or trucks.
350 and 327 [1966 - 1980]
GM engine block # 3970010 was used as early as 1968 on some 327ci engines. From 1969-1979 it was a 350ci engine. It could be a 2 or 4 bolt block used in cars, trucks and even corvettes. You can also find these blocks with a "MEXICO" stamp on them near the block ID. It has been said that these are high nickle content blocks and may be stronger than others.
The block you referenced, GM 3970010 H312, indicates that it is a Chevrolet small-block engine produced in 1969. The "H" signifies that it was manufactured in August, and "312" indicates the 312th day of that month, which corresponds to August 31, 1969. This block is commonly found in various Chevrolet vehicles from that era, particularly in high-performance applications.
4bolt 350ci
The GM engine with the casting number 3970010 is a 350 cubic inch V8 engine, commonly found in various Chevrolet vehicles from the late 1960s to the early 1980s. The stamped numbers "K1114TXL" indicate that the engine was manufactured on November 14, likely in the year 1979, with "TXL" designating it as a specific engine variant. This engine was often used in passenger cars and light trucks.
It's a 4" bore block. Has been used for 302, 327, and 350 engines.
1970 Z28...Stacy
on the block
The numbers you provided suggest that your Chevrolet 350 engine was manufactured in 1980. The casting number GM 3970010 corresponds to a 350 cubic inch engine produced between 1969 and 1980, with the suffix code V0817TBC indicating that it was assembled in August 1977 at the Van Nuys plant. Therefore, your engine most likely dates back to 1980.
The block and just about all parts have a "casting number" on them. Your block #3970010 was used by GM from 1969 through 1980 in anything from a 1/2 ton pickup, to the HOT Z-28's. It could be either a 2 bolt or a 4 bolt design. What that means is that the crankshaft is held in the engine block by main bearing caps that are designed with either 2 bolts or 4 bolts. The 2 bolt is good for non-high performance, less than 6,000 RPM's. The 4 bolt design, spreads the rotational stess over a much wider area within the block is used for over 6,000 RPM's. Hope this helps.